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Sample records for weight bearing gait

  1. On the Modulation of Brain Activation During Simulated Weight Bearing in Supine Gait-Like Stepping.

    PubMed

    Jaeger, Lukas; Marchal-Crespo, Laura; Wolf, Peter; Luft, Andreas R; Riener, Robert; Michels, Lars; Kollias, Spyros

    2016-01-01

    To date, the neurophysiological correlates of muscle activation required for weight bearing during walking are poorly understood although, a supraspinal involvement has been discussed in the literature for many years. The present study investigates the effect of simulated ground reaction forces (0, 20, and 40% of individual body weight) on brain activation in sixteen healthy participants. A magnetic resonance compatible robot was applied to render three different levels of load against the feet of the participants during active and passive gait-like stepping movements. Brain activation was analyzed by the means of voxel-wise whole brain analysis as well as by a region-of-interest analysis. A significant modulation of brain activation in sensorimotor areas by the load level could neither be demonstrated during active nor during passive stepping. These observations suggest that the regulation of muscle activation under different weight-bearing conditions during stepping occurs at the level of spinal circuitry or the brainstem rather than at the supraspinal level. PMID:26206204

  2. The effect of weight-bearing exercise and non-weight-bearing exercise on gait in rats with sciatic nerve crush injury

    PubMed Central

    Kim, Ki-Hyun; Hwangbo, Gak; Kim, Seong-Gil

    2015-01-01

    [Purpose] The purpose of this study was to access the effect of weight bearing exercise (treadmill exercise) and non-weight-bearing exercise (swimming exercise) on gait in the recovery process after a sciatic nerve crush injury. [Subjects and Methods] Rats were randomly divided into a swimming group (n=3) with non-weight-bearing exercise after a sciatic nerve crush and a treadmill group (n=3) with weight bearing exercise after a sciatic nerve crush. Dartfish is a program that can analyze and interpret motion through video images. The knee lateral epicondyle, lateral malleolus, and metatarsophalangeal joint of the fifth toe were marked by black dots before recording. [Results] There were significant differences in TOK (knee angle toe off) and ICK (knee angle at initial contact) in the swimming group and in TOK, ICA (ankle angle at initial contact), and ICK in the treadmill group. In comparison between groups, there were significant differences in TOA (ankle angle in toe off) and ICA at the 7th day. [Conclusion] There was no difference between weight bearing and non-weight-bearing exercise in sciatic nerve damage, and both exercises accelerated the recovery process in this study. PMID:25995583

  3. Effects of ankle joint mobilization with movement and weight-bearing exercise on knee strength, ankle range of motion, and gait velocity in patients with stroke: a pilot study

    PubMed Central

    An, Chang-Man; Won, Jong-Im

    2016-01-01

    [Purpose] The purpose of this study was to investigate the effects of ankle joint mobilization with movement on knee strength, ankle range of motion, and gait velocity, compared with weight-bearing exercise in stroke patients. [Subjects and Methods] Thirty subjects with chronic stroke were divided into three groups: MWM (n = 12), WBE (n = 8), and control (n = 10). All groups attended physical therapy sessions 3 times a week for 5 weeks. Subjects in the MWM group performed mobilization with movement exercises, whilst participants in the WBE group performed weight-bearing exercises. Knee peak torque, ankle range of motion, and spatiotemporal gait parameters were evaluated before and after the interventions. [Results] Knee extensor peak torque increased significantly in both MWM and WBE groups. However, only the MWM group showed significant improvement in passive and active ankle range of motion and gait velocity, among the three groups. [Conclusion] Ankle joint mobilization with movement intervention is more effective than simple weight-bearing intervention in improving gait speed in stroke patients with limited ankle motion. PMID:27065565

  4. Using gait analysis to assess weight bearing in rats with Freund׳s complete adjuvant-induced monoarthritis to improve predictivity: Interfering with the cyclooxygenase and nerve growth factor pathways.

    PubMed

    Ängeby Möller, Kristina; Berge, Odd-Geir; Finn, Anja; Stenfors, Carina; Svensson, Camilla I

    2015-06-01

    Lack of predictive power for drug effects has been a major criticism against animal pain models. It is therefore important to define the utility and limitations of different models. The aim of this study was to extend previous work on gait analysis as a tool to investigate pharmacological effects in monoarthritic rats, specifically to test the hypothesis that monoarthritis induced by Freund׳s complete adjuvant (FCA) provides a better estimate of overall analgesic efficacy of established, and novel, clinically effective and ineffective therapeutic approaches. Male rats injected intra-articularly into one ankle joint with FCA (1.0mg/ml) were treated with the monoclonal antibody to nerve growth factor (NGF), MEDI-578, the inhibitors of tropomyosin receptor kinases A, B and C (pan-Trk) AZ6623 or AZ7092, the transient receptor potential vanilloid 1 (TRPV1) inhibitor AZD1386, or the cyclooxygenase (COX) inhibitors naproxen, ibuprofen, valdecoxib or rofecoxib. Effects on weight bearing during locomotion were tested using video capture of print images. The apparent efficacy in this model was Trk inhibitors≥anti-NGF antibody>COX inhibitors. The TRPV1 inhibitor was ineffective. Together with previous data, the results support using gait-related parameters in the monoarthritis model. FCA as induction agent seems to provide a good overall prediction of analgesic efficacy in disorders with inflammatory joint pain. PMID:25792342

  5. Measuring Bearing Wear Via Weight Loss

    NASA Technical Reports Server (NTRS)

    Keba, John E.; Moore, Richard S.

    1989-01-01

    Wear in critical parts of bearings measured via amounts of weight lost during use. Technique applicable in general to bearings made of nonporous materials. Weight-loss measurements easier, faster, more precise, and less likely to damage measured parts. Weight-loss measurements performed in clean rooms and under constraint of extreme cleanliness for compatability with liquid oxygen.

  6. Aging and partial body weight support affects gait variability

    PubMed Central

    Kyvelidou, Anastasia; Kurz, Max J; Ehlers, Julie L; Stergiou, Nicholas

    2008-01-01

    Background Aging leads to increases in gait variability which may explain the large incidence of falls in the elderly. Body weight support training may be utilized to improve gait in the elderly and minimize falls. However, before initiating rehabilitation protocols, baseline studies are needed to identify the effect of body weight support on elderly gait variability. Our purpose was to determine the kinematic variability of the lower extremities in young and elderly healthy females at changing levels of body weight support during walking. Methods Ten young and ten elderly females walked on a treadmill for two minutes with a body weight support (BWS) system under four different conditions: 1 g, 0.9 g, 0.8 g, and 0.7 g. Three-dimensional kinematics was captured at 60 Hz with a Peak Performance high speed video system. Magnitude and structure of variability of the sagittal plane angular kinematics of the right lower extremity was analyzed using both linear (magnitude; standard deviations and coefficient of variations) and nonlinear (structure; Lyapunov exponents) measures. A two way mixed ANOVA was used to evaluate the effect of age and BWS on variability. Results Linear analysis showed that the elderly presented significantly more variability at the hip and knee joint than the young females. Moreover, higher levels of BWS presented increased variability at all joints as found in both the linear and nonlinear measures utilized. Conclusion Increased levels of BWS increased lower extremity kinematic variability. If the intent of BWS training is to decrease variability in gait patterns, this did not occur based on our results. However, we did not perform a training study. Thus, it is possible that after several weeks of training and increased habituation, these initial increased variability values will decrease. This assumption needs to be addressed in future investigation with both "healthy" elderly and elderly fallers. In addition, it is possible that BWS training can have a positive transfer effect by bringing overground kinematic variability to healthy normative levels, which also needs to be explored in future studies. PMID:18803851

  7. Effects of conventional overground gait training and a gait trainer with partial body weight support on spatiotemporal gait parameters of patients after stroke.

    PubMed

    Park, Byoung-Sun; Kim, Mee-Young; Lee, Lim-Kyu; Yang, Seung-Min; Lee, Won-Deok; Noh, Ji-Woong; Shin, Yong-Sub; Kim, Ju-Hyun; Lee, Jeong-Uk; Kwak, Taek-Yong; Lee, Tae-Hyun; Kim, Ju-Young; Kim, Junghwan

    2015-05-01

    [Purpose] The purpose of this study was to confirm the effects of both conventional overground gait training (CGT) and a gait trainer with partial body weight support (GTBWS) on spatiotemporal gait parameters of patients with hemiparesis following chronic stroke. [Subjects and Methods] Thirty stroke patients were alternately assigned to one of two treatment groups, and both groups underwent CGT and GTBWS. [Results] The functional ambulation classification on the affected side improved significantly in the CGT and GTBWS groups. Walking speed also improved significantly in both groups. [Conclusion] These results suggest that the GTBWS in company with CGT may be, in part, an effective method of gait training for restoring gait ability in patients after a stroke. PMID:26157272

  8. Effects of conventional overground gait training and a gait trainer with partial body weight support on spatiotemporal gait parameters of patients after stroke

    PubMed Central

    Park, Byoung-Sun; Kim, Mee-Young; Lee, Lim-Kyu; Yang, Seung-Min; Lee, Won-Deok; Noh, Ji-Woong; Shin, Yong-Sub; Kim, Ju-Hyun; Lee, Jeong-Uk; Kwak, Taek-Yong; Lee, Tae-Hyun; Kim, Ju-Young; Kim, Junghwan

    2015-01-01

    [Purpose] The purpose of this study was to confirm the effects of both conventional overground gait training (CGT) and a gait trainer with partial body weight support (GTBWS) on spatiotemporal gait parameters of patients with hemiparesis following chronic stroke. [Subjects and Methods] Thirty stroke patients were alternately assigned to one of two treatment groups, and both groups underwent CGT and GTBWS. [Results] The functional ambulation classification on the affected side improved significantly in the CGT and GTBWS groups. Walking speed also improved significantly in both groups. [Conclusion] These results suggest that the GTBWS in company with CGT may be, in part, an effective method of gait training for restoring gait ability in patients after a stroke. PMID:26157272

  9. Additional weight load increases freezing of gait episodes in Parkinson's disease; an experimental study.

    PubMed

    Mensink, Senja H G; Nonnekes, Jorik; van Bon, Geert; Snijders, Anke H; Duysens, Jacques; Weerdesteyn, Vivian; Bloem, Bastiaan R; Oude Nijhuis, Lars B

    2014-05-01

    Freezing of gait is an episodic gait disorder,characterized by the inability to generate effective forward stepping movements. The pathophysiology underlying freezing of gait remains insufficiently understood, and this hampers the development of better treatment strategies.Preliminary evidence suggests that impaired force control during walking may contribute to freezing episodes, with difficulty to unload the swing leg and initiate the swing phase. Here, we used external loading to manipulate force control and to investigate its influence on freezing of gait.Twelve Parkinson's disease patients with freezing of gait performed three contrasting tasks: (1) loaded gait while wearing a belt fortified with lead weights; (2) weight supported gait using a parachute harness connected to a rigid metal cable running above the gait trajectory; and (3)normal gait. Gait tasks were used to provoke freezing episodes, including rapid 360° turns. Freezing episodes were quantified using blinded, videotaped clinical assessment. Furthermore, ground reaction forces and body kinematics were recorded. Loading significantly increased the mean number of freezing episodes per trial compared to the normal gait condition (P<0.05), but the effect of weight support was not consistent. Loading particularly increased the number of freezing episodes during rapid short steps. Step length was significantly smaller during loaded gait compared to normal gait (P<0.05), but changes in anticipatory postural adjustments were not different.Our results may point to impaired force control playing a key role in freezing of gait. Future studies should further investigate the mechanism, i.e., the contribution of deficient load feedback, and evaluate which forms of weight support might offer treatment opportunities. PMID:24658705

  10. Grizzly bear (Ursus arctos horribilis) locomotion: gaits and ground reaction forces.

    PubMed

    Shine, Catherine L; Penberthy, Skylar; Robbins, Charles T; Nelson, O Lynne; McGowan, Craig P

    2015-10-01

    Locomotion of plantigrade generalists has been relatively little studied compared with more specialised postures even though plantigrady is ancestral among quadrupeds. Bears (Ursidae) are a representative family for plantigrade carnivorans, they have the majority of the morphological characteristics identified for plantigrade species, and they have the full range of generalist behaviours. This study compared the locomotion of adult grizzly bears (Ursus arctos horribilis Linnaeus 1758), including stride parameters, gaits and analysis of three-dimensional ground reaction forces, with that of previously studied quadrupeds. At slow to moderate speeds, grizzly bears use walks, running walks and canters. Vertical ground reaction forces demonstrated the typical M-shaped curve for walks; however, this was significantly more pronounced in the hindlimb. The rate of force development was also significantly higher for the hindlimbs than for the forelimbs at all speeds. Mediolateral forces were significantly higher than would be expected for a large erect mammal, almost to the extent of a sprawling crocodilian. There may be morphological or energetic explanations for the use of the running walk rather than the trot. The high medial forces (produced from a lateral push by the animal) could be caused by frontal plane movement of the carpus and elbow by bears. Overall, while grizzly bears share some similarities with large cursorial species, their locomotor kinetics have unique characteristics. Additional studies are needed to determine whether these characters are a feature of all bears or plantigrade species. PMID:26254319

  11. Neuromuscular Fatigue and Tibiofemoral Joint Biomechanics When Transitioning From Non–Weight Bearing to Weight Bearing

    PubMed Central

    Schmitz, Randy J.; Kim, Hyunsoo; Shultz, Sandra J.

    2015-01-01

    Context: Fatigue is suggested to be a risk factor for anterior cruciate ligament injury. Fatiguing exercise can affect neuromuscular control and laxity of the knee joint, which may render the knee less able to resist externally applied loads. Few authors have examined the effects of fatiguing exercise on knee biomechanics during the in vivo transition of the knee from non–weight bearing to weight bearing, the time when anterior cruciate ligament injury likely occurs. Objective: To investigate the effect of fatiguing exercise on tibiofemoral joint biomechanics during the transition from non–weight bearing to early weight bearing. Design: Cross-sectional study. Setting: Research laboratory. Patients or Other Participants: Ten participants (5 men and 5 women; age = 25.3 ± 4.0 years) with no previous history of knee-ligament injury to the dominant leg. Intervention(s): Participants were tested before (preexercise) and after (postexercise) a protocol consisting of repeated leg presses (15 repetitions from 10°–40° of knee flexion, 10 seconds' rest) against a 60% body-weight load until they were unable to complete a full bout of repetitions. Main Outcome Measure(s): Electromagnetic sensors measured anterior tibial translation and knee-flexion excursion during the application of a 40% body-weight axial compressive load to the bottom of the foot, simulating weight acceptance. A force transducer recorded axial compressive force. Results: The axial compressive force (351.8 ± 44.3 N versus 374.0 ± 47.9 N; P = .018), knee-flexion excursion (8.0° ± 4.0° versus 10.2° ± 3.7°; P = .046), and anterior tibial translation (6.7 ± 1.7 mm versus 8.2 ± 1.9 mm; P < .001) increased from preexercise to postexercise. No significant correlations were noted. Conclusions: Neuromuscular fatigue may impair initial knee-joint stabilization during weight acceptance, leading to greater accessory motion at the knee and the potential for greater anterior cruciate ligament loading. PMID:25375932

  12. The Combined Effects of Body Weight Support and Gait Speed on Gait Related Muscle Activity: A Comparison between Walking in the Lokomat Exoskeleton and Regular Treadmill Walking

    PubMed Central

    Van Kammen, Klaske; Boonstra, Annemarijke; Reinders-Messelink, Heleen; den Otter, Rob

    2014-01-01

    Background For the development of specialized training protocols for robot assisted gait training, it is important to understand how the use of exoskeletons alters locomotor task demands, and how the nature and magnitude of these changes depend on training parameters. Therefore, the present study assessed the combined effects of gait speed and body weight support (BWS) on muscle activity, and compared these between treadmill walking and walking in the Lokomat exoskeleton. Methods Ten healthy participants walked on a treadmill and in the Lokomat, with varying levels of BWS (0% and 50% of the participants’ body weight) and gait speed (0.8, 1.8, and 2.8 km/h), while temporal step characteristics and muscle activity from Erector Spinae, Gluteus Medius, Vastus Lateralis, Biceps Femoris, Gastrocnemius Medialis, and Tibialis Anterior muscles were recorded. Results The temporal structure of the stepping pattern was altered when participants walked in the Lokomat or when BWS was provided (i.e. the relative duration of the double support phase was reduced, and the single support phase prolonged), but these differences normalized as gait speed increased. Alternations in muscle activity were characterized by complex interactions between walking conditions and training parameters: Differences between treadmill walking and walking in the exoskeleton were most prominent at low gait speeds, and speed effects were attenuated when BWS was provided. Conclusion Walking in the Lokomat exoskeleton without movement guidance alters the temporal step regulation and the neuromuscular control of walking, although the nature and magnitude of these effects depend on complex interactions with gait speed and BWS. If normative neuromuscular control of gait is targeted during training, it is recommended that very low speeds and high levels of BWS should be avoided when possible. PMID:25226302

  13. Ankle muscle coactivation during gait is decreased immediately after anterior weight shift practice in adults after stroke.

    PubMed

    Kitatani, Ryosuke; Ohata, Koji; Sakuma, Kaoru; Aga, Yumi; Yamakami, Natsuki; Hashiguchi, Yu; Yamada, Shigehito

    2016-03-01

    Increased ankle muscle coactivation during gait has frequently been observed as an adaptation strategy to compensate for postural instability in adults after stroke. However, it remains unclear whether the muscle coactivation pattern increases or decreases after balance training. The aim of this study was to investigate the immediate effects of balance practice on ankle muscle coactivation during gait in adults after stroke. Standing balance practice performed to shift as much weight anteriorly as possible in 24 participants after stroke. The forward movement distance of the center of pressure (COP) during anterior weight shifting, gait speed, and ankle muscle activities during 10-m walking tests were measured immediately before and after balance practice. Forward movement of the COP during anterior weight shifting and gait speed significantly increased after balance practice. On the paretic side, tibialis anterior muscle activity significantly decreased during the single support and second double support phases, and the coactivation index at the ankle joint during the first double support and single support phases significantly decreased after balance practice. However, there were no significant relationships between the changes in gait speed, forward movement of the COP during anterior weight shifting, and ankle muscle coactivation during the stance phase. These results suggested that ankle muscle coactivation on the paretic side during the stance phase was decreased immediately after short-term anterior weight shift practice, which was not associated with improved gait speed or forward movement of the COP during anterior weight shifting in adults after stroke. PMID:26979880

  14. Improvement of gait ability with a short-term intensive gait rehabilitation program using body weight support treadmill training in community dwelling chronic poststroke survivors

    PubMed Central

    Takao, Toshifumi; Tanaka, Naoki; Iizuka, Noboru; Saitou, Hideyuki; Tamaoka, Akira; Yanagi, Hisako

    2015-01-01

    [Purpose] Most previous studies have shown that body weight support treadmill training (BWSTT) can improve gait speed poststroke patients. The purpose of this study was to evaluate effectiveness of a short-term intensive program using BWSTT among community dwelling poststroke survivors. [Subjects] Eighteen subjects participated in this study. The treatment group was composed of 10 subjects (2 women; 8 men; mean age, 59.1 ± 12.5 years; time since stroke onset, 35.3 ± 33.2 months), whereas the control group was made up of 8 subjects (3 women; 5 men; mean age, 59.8 ± 6.3 years; time since stroke onset, 39.3 ± 27.3 months). [Methods] The treatment group received BWSTT 3 times a week for 4 weeks (a total of 12 times), with each session lasting 20 minutes. The main outcome measures were maximum gait speed on a flat floor, cadence, and step length. [Results] No differences were observed in the baseline clinical data between the 2 groups. The gait speed in the treatment group was significantly improved compared with that in the control by 2-way ANOVA, while the other parameters showed no significant interaction. [Conclusion] These results suggested that short-term intensive gait rehabilitation using BWSTT was useful for improving gait ability among community dwelling poststroke subjects. PMID:25642063

  15. Excess Body Weight Loss is Associated with Nonpathological Gait Patterns in Women 4 to 5 Years After Bariatric Surgery

    PubMed Central

    Laughlin, Richard T.; Teel, Donovan D.; Sherwood, Richard J.; Duren, Dana L.

    2014-01-01

    Background This study examined relationships between excess body weight (EBW) loss and current gait and functional status in women 5 years after Roux-en-Y gastric bypass surgery. Methods Gait data were analyzed in nine female bariatric patients for relationships with longitudinal changes in weight, body composition, and physical function assessed by the Short Musculoskeletal Functional Assessment (SMFA) questionnaire and the timed “get-up-and-go” (TGUG) test. Gait characteristics in the bariatric sample were also compared to an age- and BMI-matched nonsurgical reference sample from the Fels Longitudinal Study. Results Bariatric patients lost an average of 36.4 kg (61.1 %) of EBW between preoperative and 5-year follow-up visits (P <0.01); SMFA function index scores and TGUG times also decreased (both P <0.01). Degree of EBW loss was correlated with less time spent in initial double support and more time in single support (both P =0.02), and for all gait variables, the bariatric sample fell within the 95 % confidence intervals of gait/EBW relationships in the reference sample. Conclusions Gait and function 5 years after bariatric surgery were characteristic of current weight, not preoperative obesity, suggesting that substantial, sustained recovery of physical function is possible with rapid surgical weight loss. PMID:24008625

  16. Foot Loading Characteristics of Different Graduations of Partial Weight Bearing

    ERIC Educational Resources Information Center

    Gusinde, Johannes; Pauser, Johannes; Swoboda, Bernd; Gelse, Kolja; Carl, Hans-Dieter

    2011-01-01

    Limited weight bearing of the lower extremity is a commonly applied procedure in orthopaedic rehabilitation after reconstructive forefoot surgery, trauma surgery and joint replacement. The most frequent limitations are given as percentage of body weight (BW) and represent 10 or 50% BW. The extent of foot loading under these graduations of partial

  17. Foot Loading Characteristics of Different Graduations of Partial Weight Bearing

    ERIC Educational Resources Information Center

    Gusinde, Johannes; Pauser, Johannes; Swoboda, Bernd; Gelse, Kolja; Carl, Hans-Dieter

    2011-01-01

    Limited weight bearing of the lower extremity is a commonly applied procedure in orthopaedic rehabilitation after reconstructive forefoot surgery, trauma surgery and joint replacement. The most frequent limitations are given as percentage of body weight (BW) and represent 10 or 50% BW. The extent of foot loading under these graduations of partial…

  18. Temporospatial and kinematic gait alterations during treadmill walking with body weight suspension.

    PubMed

    Threlkeld, A Joseph; Cooper, Lance D; Monger, Brock P; Craven, Aric N; Haupt, Howard G

    2003-06-01

    Our purpose was to analyze the effects of selected levels of body weight support (BWS) on lower extremity kinematics of normal subjects at a predetermined treadmill speed. Seventeen non-disabled volunteers walked on a treadmill at 1.25 ms(-1). Temporospatial and kinematic data were collected while various support levels were applied (Minimal, 10, 30, 50 and 70% BWS). Compared to 10% BWS, significant temporospatial and kinematic changes were induced by 50 and 70% BWS. Fewer differences were induced by 30% BWS compared to 10% BWS. We concluded that gait patterns of unimpaired subjects are significantly changed by 50 and 70% BWS. PMID:12770637

  19. Design of a mechanical system in gait rehabilitation with progressive addition of weight

    NASA Astrophysics Data System (ADS)

    Braidot, Ariel A. A.; Aleman, Guillermo L.

    2011-12-01

    In this paper we designed and developed a mechanical device for gait rehabilitation based on the application of "partial body weight reduction therapy". An evaluation of the characteristics of devices based on this therapy currently available on the market was carried out obtaining information of the different mechanisms used in it. The device was designed to adapt to different height and weight of patients and to be used with additional equipment in gait rehabilitation, for example, treadmills, elliptical trainers and vertical scalers. It was envisaged to be used by patients with asymmetry in the lower extremities capabilities. We developed a stable structure in steel ASTM A36 which does not depend on the building conditions of the installation site. RamAdvanse software was used to calculate structural stability. A winch with automatic brake mechanism was used to raise/lower the patient, who was tied to a comfortable harness which provided safety to the patient and therapist. It was possible to quantify precisely, using counterweights, the weight borne by the patient during therapy. We obtained a small-sized and ergonomic low-cost prototype, with similar features to those currently considered cutting-edge devices.

  20. Effects of Functional Limb Overloading on Symmetrical Weight Bearing, Walking Speed, Perceived Mobility, and Community Participation among Patients with Chronic Stroke.

    PubMed

    Alabdulwahab, Sami S; Ahmad, Fuzail; Singh, Harpreet

    2015-01-01

    Background. Stroke is a leading cause for long-term disability that often compromises the sensorimotor and gait function accompanied by spasticity. Gait abnormalities persist through the chronic stages of the condition and only a small percentage of these persons are able to walk functionally in the community. Material and Method. Patients with chronic stroke were recruited from outpatient rehabilitation unit at Department of Neurology & Neurosurgery, All India Institute of Medical Sciences, having a history of first stroke at least six months before recruitment, with unilateral motor deficits affecting gait. The patients were randomly assigned to either the functional limb overloading (FLO) or Limb Overloading Resistance Training (LORT) group and provided four weeks of training. Result. We found that there was an improvement in gait performance, weight bearing on affected limb, and perceived mobility and community participation. Conclusion. To the best of our knowledge, this is the first study that has evaluated the effects of functional limb overloading training on symmetric weight bearing, walking ability, and perceived mobility and participation in chronic hemiplegic population. The study demonstrated a beneficial effect of training on all the outcomes, suggesting that the functional limb overloading training can be a useful tool in the management of gait problems in chronic stroke patients. PMID:26600952

  1. Effects of Functional Limb Overloading on Symmetrical Weight Bearing, Walking Speed, Perceived Mobility, and Community Participation among Patients with Chronic Stroke

    PubMed Central

    Alabdulwahab, Sami S.; Ahmad, Fuzail; Singh, Harpreet

    2015-01-01

    Background. Stroke is a leading cause for long-term disability that often compromises the sensorimotor and gait function accompanied by spasticity. Gait abnormalities persist through the chronic stages of the condition and only a small percentage of these persons are able to walk functionally in the community. Material and Method. Patients with chronic stroke were recruited from outpatient rehabilitation unit at Department of Neurology & Neurosurgery, All India Institute of Medical Sciences, having a history of first stroke at least six months before recruitment, with unilateral motor deficits affecting gait. The patients were randomly assigned to either the functional limb overloading (FLO) or Limb Overloading Resistance Training (LORT) group and provided four weeks of training. Result. We found that there was an improvement in gait performance, weight bearing on affected limb, and perceived mobility and community participation. Conclusion. To the best of our knowledge, this is the first study that has evaluated the effects of functional limb overloading training on symmetric weight bearing, walking ability, and perceived mobility and participation in chronic hemiplegic population. The study demonstrated a beneficial effect of training on all the outcomes, suggesting that the functional limb overloading training can be a useful tool in the management of gait problems in chronic stroke patients. PMID:26600952

  2. Weights and hematology of wild black bears during hibernation

    USGS Publications Warehouse

    DelGiudice, Glenn D.; Rogers, Lynn L.; Allen, Arthur W.; Seal, U.S.

    1991-01-01

    We compared weights and hematological profiles of adult (greater than 3-yr-old) female black bears (Ursus americanus) during hibernation (after 8 January). We handled 28 bears one to four times (total of 47) over 4 yr of varying mast and berry production. Mean weight of lactating bears was greater (P less than 0.0001) than that of non-lactating females. White blood cells (P less than 0.05) and mean corpuscular volume (P = 0.005) also differed between lactating and non-lactating bears. Hemoglobin (P = 0.006) and mean corpuscular hemoglobin concentration (P = 0.02) varied among years; values were lowest during 1975, following decreased precipitation and the occurrence of a second year of mast and berry crop shortages in a three-year period. Significant (P less than 0.05) interaction between reproductive status (lactating versus non-lactating) and study year for hemoglobin, red blood cells, and packed cell volume, and increased mean corpuscular volume, suggested a greater nutritional challenge for lactating females compared to non-lactating females during the 1975 denning season. Our data suggest that hematological characteristics of denning bears may be more sensitive than weights as indicators of annual changes in nutritional status; however, other influential factors, in addition to mast and berry crop production, remain to be examined.

  3. The effect of increase in baggage weight on elderly women's lower extremity muscle activation during gait.

    PubMed

    Kim, Seong-Gil; Nam, Chan-Woo; Yong, Min-Sik

    2014-01-01

    The aim of the present study was to examine the effect of increased baggage weight on the muscle activation of elderly women's lower extremities during gait. A total of 24 elderly women who were residing in communities in Daegu, South Korea aged 79.6±6.2, 149.7±7.0cm in height, and 53.5±7.2kg in weight participated in this study. The muscle activation of each muscle was measured three times at 2kg, 3kg, and 4kg of baggage weight while the subjects were conducting treadmill walking wearing backpacks. Electrodes were placed on four muscles: the quadriceps muscle (rectus femoris), the hamstring muscle (semitendinosus), the tibialis anterior muscle, and the soleus muscle. The results show that the rates of increase in muscle activation in the tibialis anterior and soleus muscles according to baggage weight increase were higher than those in the quadriceps and hamstring muscles (<0.05). These results indicate that the heavier weight loads increase the activation of muscles that control the ankle joints causing muscle fatigue. Moreover, a decrease in balance ability through muscle fatigue can be a risk factor for falls. Thus, elderly people should be instructed not to carry heavy objects. PMID:25179442

  4. Weight-bearing plantar reconstruction using versatile medial plantar sensate flap.

    PubMed

    Oh, Suk Joon; Moon, Mincheol; Cha, Jeongho; Koh, Sung Hoon; Chung, Chul Hoon

    2011-02-01

    The medial plantar flap serves as an ideal tissue reserve for reconstructing the weight-bearing plantar areas as these areas require a sensate and glabrous skin. Furthermore, the flap provides tissue that is structurally similar to the plantar foot as it is also composed of thick glabrous plantar skin, shock-absorbing fibro-fatty subcutaneous tissue and plantar fascia. During the past 25 years, 20 patients (10 men, 10 women) with skin and soft-tissue defects over the weight-bearing plantar foot were treated. They ranged in age from 20 to 70 years (mean, 31.5 years). The causes of the defects were trauma (n=14) and malignant tumour (n=6); the defects were localised at the heel (n=16) and plantar forefoot (n=4). The medial plantar flap was transposed to the defects in three different ways: proximally pedicled sensorial island flaps (n =8), distally pedicled sensate island flaps based on the lateral plantar vessel (n =3) and neurovascular free flaps (n =9). Flap size varied from a width of 4-8cm and a length of 6-12cm. The mean size of the medial plantar flap was 49.5cm(2) (range, 28-96cm(2)). The follow-up period ranged from 6 to 80 months (mean, 19.9 months). Partial flap loss was observed in two proximally pedicled sensorial island flaps and one distally pedicled sensate island flap. Two free flaps restored normal sensation within 5 years of surgery. Minor skin graft loss at the donor site was observed in seven patients. However, no revision or re-grafting was performed. Hyperkeratosis was observed in one case. All patients achieved normal gait within 3 months after surgery and none noticed recurred ulceration. Durable, sensate coverage of the defects was achieved in all patients. We advocate variable sensate medial plantar flaps for the reconstruction of moderate-size defects of the weight-bearing plantar subunits. PMID:20570228

  5. Weight Bearing Asymmetry and Functional Ambulation Performance in Stroke Survivors

    PubMed Central

    Adegoke, B. O. A.; Olaniyi, O.; Akosile, C. O.

    2012-01-01

    This study evaluated asymmetry of weight bearing on the lower limbs and the association between percentage weight bearing asymmetry (PWBA) and functional ambulation performance in ambulant stroke survivors. Participants were 53 stroke survivors (male = 35, female = 18) aged 40-86 years (mean=58.87; SD=9.21years) with hemiparesis. Weight bearing through the lower limbs in standing was assessed by two juxtaposed bathroom weighing scales while functional ambulation performance was evaluated with the Emory Functional Ambulation Profile (E-FAP). Data were summarized with mean and standard deviation and further analyzed using the Pearson product moment correlation at 0.05 alpha level. Participants bore 60.3% (SD =7.1%) of their body weights on the unaffected legs and had a mean PWBA of 20.8 % (SD=14.7%). There was a significant positive correlation (r = 0.675, p < 0.0001) between PWBA and total E-FAP scores of participants. PWBA could hence be used to monitor functional ambulation recovery in stroke survivors. PMID:22980155

  6. Determinants of bone density among athletes engaged in weight-bearing and non-weight-bearing activity

    NASA Technical Reports Server (NTRS)

    Block, Jon E.; Friedlander, Anne L.; Brooks, George A.; Steiger, Peter; Stubbs, Harrison A.

    1989-01-01

    The effect of weight bearing activity on the bone density was investigated in athletes by comparing the measures of bone density of athletes engaged in weight-training programs with those of polo players and nonexercising subjects. All subjects had measurements of spinal trabecular and integral bone density by quantitative tomography, as well as determinations of hip bone density by dual photon absorptiometry. Results confirmed previous findings by Block et al. (1987) of significantly greater bone density among highly trained athletes compared with nonexercising subjects of similar age. Results also indicated that athletes engaged in non-weight-bearing forms of rigorous exercise had greater levels of bone density. However, as the participants in this study were exceptional athletes, engaged in a strenuous sport with both aerobic and heavy resistance components, a confirmation of these data is needed, using larger samples of individuals.

  7. Early weight bearing of lateral tibial plateau fractures.

    PubMed

    Segal, D; Mallik, A R; Wetzler, M J; Franchi, A V; Whitelaw, G P

    1993-09-01

    From 1975 to 1984, 134 consecutive lateral tibial plateau fractures were treated as part of this prospective study. Eighty-six fractures (64%) were followed until union, with an average follow-up period of 22.7 months. The two aims of this study were: First, to analyze the results of operative and nonoperative therapy in each fracture type, and second, to evaluate the effect of early weight bearing in a cast brace in both types of treatment. All lateral tibial plateau fractures with greater than 5 mm depression or displacement were treated operatively. Forty-four patients were treated operatively and 42 patients nonoperatively. All patients were treated with early range of motion and weight bearing in a cast brace. Fractures were initially classified using Hohl's classification system. Overall, 95% of the patients with Type I, II, or V fractures had satisfactory results, as opposed to only 70% of patients with Type III fractures. Of the Type III fractures, 83% treated operatively had satisfactory results compared with 53% treated nonoperatively. Moreover, early weight bearing did not produce further depression greater than 2 mm. PMID:8358921

  8. Eccentric exercise training as a countermeasure to non-weight-bearing soleus muscle atrophy

    NASA Technical Reports Server (NTRS)

    Kirby, Christopher R.; Ryan, Mirelle J.; Booth, Frank W.

    1992-01-01

    This investigation tested whether eccentric resistance training could prevent soleus muscle atrophy during non-weight bearing. Adult female rats were randomly assigned to either weight bearing +/- intramuscular electrodes or non-weight bearing +/- intramuscular electrodes groups. Electrically stimulated maximal eccentric contractions were performed on anesthetized animals at 48-h intervals during the 10-day experiment. Non-weight bearing significantly reduced soleus muscle wet weight (28-31 percent) and noncollagenous protein content (30-31 percent) compared with controls. Eccentric exercise training during non-weight bearing attenuated but did not prevent the loss of soleus muscle wet weight and noncollagenous protein by 77 and 44 percent, respectively. The potential of eccentric exercise training as an effective and highly efficient counter-measure to non-weight-bearing atrophy is demonstrated in the 44 percent attenuation of soleus muscle noncollagenous protein loss by eccentric exercise during only 0.035 percent of the total non-weight-bearing time period.

  9. Pediatric Obesity and Perceived Exertion: Difference Between Weight-Bearing and Non-Weight-Bearing Exercises Performed at Different Intensities.

    PubMed

    Thivel, D; Isacco, L; O'Malley, G; Duché, P

    2016-03-01

    Excess body weight composes an important limitation to exercise in obese youth. The aim of this study was to compare the perceived exertion of obese adolescents between weight-bearing (WB; running) and non-weight-Bearing (NWB; cycling) exercises performed at moderate (55%VO2max) and high (75%VO2max) intensities. Twenty-four obese adolescents were recruited. After assessment of their body composition and physical capacities, they had to complete four isoenergetic exercise sessions: (1) a cycling session performed at 55% of their maximal capacities (NWB-55%); (2) a cycling session set at 75% (NWB-75%); (3) a running session at 55% (WB-55%); and (4) a running session at 75% (WB-75%). Perceived exertion was assessed using a visual scale at regular interval. While no significant difference between WB and NWB modalities was observed, the adolescents expressed a significantly lower rate of perceived exertion (RPE) during exercises at 55%VO2max (P < 0.0001). An intensity × modality interaction revealed that RPE was lower at 75% VO2max during NWB exercises (P < 0.05). While obese adolescents expressed lower RPE during exercise at moderate intensity whatever its modality, low level of perceived exertion has been observed during high-intensity exercises and especially during NWB. High-intensity exercise appears well tolerated in adolescents when their body weight is supported. PMID:26090822

  10. Temporal-spatial gait parameters and neurodevelopment in very-low-birth-weight preterm toddlers at 18-22 months.

    PubMed

    Cahill-Rowley, Katelyn; Rose, Jessica

    2016-03-01

    Children born preterm with very-low birth-weight (VLBW) have increased risk of motor impairment. Early identification of impairment guides treatment to improve long-term function. Temporal-spatial gait parameters are an easily-recorded assessment of gross motor function. The objective of this study was to characterize preterm toddlers' gait and its relationship with neurodevelopment. Velocity, cycle time, step width, step length and time asymmetry, %stance, %single-limb support, and %double-limb support were calculated for 81 VLBW preterm and 43 typically-developing (TD) toddlers. Neurodevelopment was assessed with Bayley Scales of Infant Development-3rd Edition (BSID-III) motor composite and gross motor scores. Mean step width (p=.009) was wider in preterm compared to TD toddlers. Preterm toddlers with <85 BSID-III motor composite scores, indicating mild-to-moderate delay, had significantly increased step width, step length asymmetry, and step time compared to TD toddlers. Step time was also significantly longer for lower-scoring compared to higher-scoring (≥85 BSID-III motor composite scores) preterm toddlers, suggesting that step time may be particularly sensitive to gradations of motor performance. Velocity, cycle time, step length asymmetry, %stance, step length, and step time significantly correlated with BSID-III gross motor scores, suggesting that these parameters may be revealing of gross motor function. The differences in gait between lower-scoring preterm toddlers and TD toddlers, together with the correlations between gait and BSID-III motor scores, suggest that temporal-spatial gait parameters may be useful in building a clinically-relevant, easily-conducted assessment of toddler gross motor development. PMID:26979887

  11. Method for estimating maximum permissible load weight for Japanese native horses using accelerometer-based gait analysis.

    PubMed

    Matsuura, Akihiro; Irimajiri, Mami; Matsuzaki, Kunihiro; Hiraguri, Yuko; Nakanowatari, Toshihiko; Yamazaki, Atusi; Hodate, Koichi

    2013-01-01

    The aim of this study was to establish a method for estimating loading capacity for Japanese native horses by gait analysis using an accelerometer. Six mares of Japanese native horses were used. The acceleration of each horse was recorded during walking and trotting along a straight course at a sampling frequency of 200 Hz. Each horse performed 12 tests: one test with a loaded weight of 80 kg (First 80 kg) followed by 10 tests with random loaded weights between 85 kg and 130 kg and a final test with a loaded weight of 80 kg again. The time series of acceleration was subjected to fast Fourier transformation, and the autocorrelation coefficient was calculated. The first two peaks of the autocorrelation were defined as symmetry and regularity of the gait. At trot, symmetries in the 100, 110, and 125 kg tests were significantly lower than that in First 80 kg (P < 0.05, by analysis of covariance and Sidak's test). These results imply that the maximum permissible load weight is less than 100 kg, which is 29% of the body weight of Japanese native horses. Our method is a widely applicable and welfare-friendly method for estimating maximum permissible load weights of horses. PMID:23302086

  12. Bone density at weight-bearing and nonweight-bearing sites in ballet dancers: the effects of exercise, hypogonadism, and body weight.

    PubMed

    Young, N; Formica, C; Szmukler, G; Seeman, E

    1994-02-01

    Exercise is recommended as a means of preventing osteoporosis. When intensive, weight-bearing exercise is often associated with hypogonadism. As weight-bearing exercise is likely to be more beneficial at weight-bearing than nonweight-bearing sites, and hypogonadism is likely to be more detrimental to trabecular than cortical bone, we tested the hypothesis that exercise and hypogonadism result in differing regional effects: net benefits at weight-bearing, predominantly cortical sites, and net deficits at nonweight-bearing trabecular-rich sites. Bone density (grams per cm2), body fat, and fat-free mass (kilograms) were measured using dual x-ray absorptiometry in 44 ballet dancers, aged 17.0 +/- 0.2 yr (mean +/- SEM), 18 sedentary amenorrheic girls with anorexia nervosa, and 23 girls of comparable age with regular menstrual cycles. Bone density, expressed as a percentage above or below the mean in the girls with regular menstrual cycles, was normal or elevated at weight-bearing sites in dancers [femoral neck, 3.1 +/- 1.7% (P = NS); Wards triangle, 4.1 +/- 2.3% (P = NS); trochanter, 5.9 +/- 1.9% (P < 0.05)] and normal or reduced at these sites in girls with anorexia nervosa [-10.5 +/- 3.8% (P < 0.05), -7.8 +/- 4.3% (P = NS), and -8.7 +/- 4.0% (P < 0.05), respectively]. By contrast, deficits similar to those in girls with anorexia nervosa were found in dancers at nonweight-bearing sites [ribs, -5.7 +/- 0.8% (P < 0.01); arms, -4.6 +/- 1.1% (P < 0.01); skull, -5.9 +/- 1.3% (P < 0.01)] before, but not after, correcting for fat mass. Fat mass was 7.8 +/- 0.4 kg in dancers, similar to that in girls with anorexia nervosa (6.3 +/- 0.7 kg) and lower than that in girls with regular menstrual cycles (16.8 +/- 1.6 kg; P < 0.01). The net result of vigorous exercise, hypogonadism, and leanness in athletic amenorrhea may not be generalized osteoporosis. Weight-bearing exercise may offset the effects of hypogonadism at predominantly cortical weight-bearing sites, such as the proximal femur. Non-weight-bearing sites and weight-bearing sites containing substantial amounts of trabecular bone, such as the lumbar spine, may be adversely affected by hypogonadism while benefiting little from weight-bearing exercise. Deficits at nonweight-bearing sites may be attenuated by maintenance of body weight. PMID:8106634

  13. Measuring polyethylene wear in total knee arthroplasty by RSA: differences between weight-bearing and non-weight-bearing positioning.

    PubMed

    van Ijsseldijk, Emiel A; Valstar, Edward R; Stoel, Berend C; de Ridder, Ruud; Nelissen, Rob G H H; Kaptein, Bart L

    2014-04-01

    Measuring the minimum-joint-space-width (mJSW) in total knee arthroplasty (TKA) in Roentgen stereophotogrammetric analysis (RSA) provides valuable information on polyethylene wear, a leading cause for TKA failure. Most existing studies use non-weight-bearing (NWB) patient positioning. The latter may compromise mJSW measurements due to knee laxity with subsequent non-contact between the TKA components. We investigated the difference in mJSW between weight-bearing (WB) and NWB images and the association with mediolateral (ML) knee stability. At one-year follow-up, 23 TKAs were included from an ongoing RSA study, and ML stability was evaluated. For each examination, the mJSW and femoral-tibial contact locations were measured. A linear regression model was used to analyze the association between the mJSW difference (NWB-WB) with the ML stability and contact locations. The mean mJSW difference was 0.28 mm medially and 0.20 mm laterally. Four TKAs had medium (5-9°) and 19 TKAs had high (<5°) ML stability. A higher mJSW difference was found for TKAs with medium stability (0.36 mm, P = 0.01). In conclusion, mJSW measurements in existing (NWB) RSA studies are influenced by knee laxity, but may still provide information on wear progression based on TKA with high ML stability. A direct comparison of mJSW measurements from WB and NWB data is not possible. PMID:24395396

  14. Changes in skeletal muscle gene expression consequent to altered weight bearing

    NASA Technical Reports Server (NTRS)

    Booth, F. W.; Kirby, C. R.

    1992-01-01

    Skeletal muscle is a dynamic organ that adapts to alterations in weight bearing. This brief review examines changes in muscle gene expression resulting from the removal of weight bearing by hindlimb suspension and from increased weight bearing due to eccentric exercise. Acute (less than or equal to 2 days) non-weight bearing of adult rat soleus muscle alters only the translational control of muscle gene expression, while chronic (greater than or equal to 7 days) removal of weight bearing appears to influence pretranslational, translational, and posttranslational mechanisms of control. Acute and chronic eccentric exercise are associated with alterations of translational and posttranslational control, while chronic eccentric training also alters the pretranslational control of muscle gene expression. Thus alterations in weight bearing influence multiple sites of gene regulation.

  15. Syme's amputation. Follow-up study of weight-bearing in sixty-eight patients.

    PubMed

    Hornby, R; Harris, R

    1975-04-01

    Sixty-eight patients with Syme amputations resulting from industrial injuries were reviewed. The amount of end-weight-bearing was measured with a capacitance transducer. The majority of patients required fitting with a prosthesis designed to relieve end-weight-bearing. The old-fashioned prosthesis with a leather corset was the most effective in achieving reduction of end-weight-bearing. PMID:1123389

  16. Weight-Bearing Exercise and Foot Health in Native Americans

    PubMed Central

    Cuaderes, Elena; DeShea, Lise; Lamb, W. Lyndon

    2015-01-01

    Diabetes contributes to sensory peripheral neuropathy, which has been linked to lower limb abnormalities that raise the risk for foot ulcers and amputations. Because amputations are a reason for pain and hospitalization in those with diabetes, it is of critical importance to gain insight about prevention of ulcer development in this population. Although the American Diabetes Association (ADA) now recommends that individuals with neuropathy can engage in moderate-intensity weight-bearing activity (WBA), they must wear appropriate footwear and inspect their feet daily. The physical forces and inflammatory processes from WBA may contribute to plantar characteristics that lead to ulcers. The purpose of this study was to compare neuropathic status and foot characteristics in Native Americans according to WBA classification. The t tests for unequal sample sizes found that exercisers had more difficulty sensing baseline temperature than nonexercisers, except at the right foot (all p values < .05). By dividing groups into no/low risk and high risk for ulcer, a majority showed no/low risk according to touch and vibration sense. Exercisers demonstrated higher surface skin temperature gradients at the first metatarsal head, a plantar site where wounds tend to form. The more consistently exercisers performed, the higher the plan-tar pressures were at the right second (r = .24, p = .02) and third metatarsal heads (r = .26, p = .01). Findings from this investigation do not refute current ADA recommendations and further intervention studies are needed that are longitudinal and measures WBA more accurately. PMID:26294899

  17. Effect of a textured insole on balance and gait symmetry.

    PubMed

    Aruin, Alexander S; Kanekar, Neeta

    2013-11-01

    Asymmetry of standing balance and gait is common in individuals with neurological disorders, and achieving symmetrical stance and gait is an important goal of rehabilitation. The purpose of this study was to investigate the effect of a novel discomfort-induced approach (that is based on using a single textured insole) on the alteration in the symmetry of gait and balance. Eleven healthy subjects (6 females and 5 males, mean age of 28.0 ± 4.1 years) were tested using the Computerized Dynamic Posturography and GaitRite systems when standing or walking while wearing standard footwear with the textured insole positioned either in the left or in the right shoe, and without the insole. Significant immediate effect of the textured insole was seen in the outcome measures of static (weight bearing) and dynamic (weight symmetry index, strength symmetry) balance tests (p < 0.05) as well as in gait symmetry (single support and swing phases) (p < 0.05). The results of the study indicate that a textured insole can significantly modify the symmetry of stance and gait in healthy individuals. Pilot data from individuals with stroke also showed a reduction in the asymmetry of gait when walking with the single textured insole in the shoe on the unaffected side. This outcome provides support for future studies on the efficacy of the textured insole in minimizing asymmetry of gait and posture in individuals in need. PMID:23979014

  18. Current advances in training orthopaedic patients to comply with partial weight-bearing instructions.

    PubMed

    Hustedt, Joshua W; Blizzard, Daniel J; Baumgaertner, Michael R; Leslie, Michael P; Grauer, Jonathan N

    2012-03-01

    Partial weight-bearing instructions are commonly given to orthopaedic patients and are an important part of post-injury and/or post-operative care. However, the ability of patients to comply with these instructions is poorly defined. Training methods for instructing these patients vary widely among institutions. Traditional methods of training include verbal instruction and use of a bathroom scale. Recent technological advances have created biofeedback devices capable of offering feedback to partial weight-bearing patients. Biofeedback devices have shown great promise in training patients to better comply with partial weight-bearing instructions. This review examines the background and significance of partial weight bearing and offers insights into current advances in training methods for partial weight-bearing patients. PMID:22461750

  19. Effects of Weight-Bearing Biofeedback Training on Functional Movement Patterns Following Total Knee Arthroplasty: A Randomized Controlled Trial

    PubMed Central

    Christiansen, Cory L.; Bade, Michael J.; Davidson, Bradley S.; Dayton, Michael R.; Stevens-Lapsley, Jennifer E.

    2015-01-01

    STUDY DESIGN Randomized controlled trial. OBJECTIVES Examine the effects of weight-bearing (WB) biofeedback training on WB symmetry and functional joint moments following unilateral total knee arthroplasty (TKA). BACKGROUND Individuals post unilateral TKA place more weight on the non-surgical limb compared to the surgical limb during function. It is unknown if targeted intervention can improve surgical limb use and resolve altered movement patterns. METHODS Twenty-six patients were randomized to 2 groups: RELOAD or CONTROL. The RELOAD group had standard of care rehabilitation augmented with WB biofeedback training and the CONTROL group had dose-matched standard of care. Lower limb weight-bearing ratios (WBRs) were measured preoperatively and 6 and 26 weeks after TKA during a Five Times Sit-to-Stand Test (FTSST) and walking. Secondary outcomes were FTSST time, walking speed, and lower limb joint moments during the FTSST and walking. RESULTS No between-group differences were found in WBR. FTSST time improved in the RELOAD group compared to the CONTROL group at 6 (P=.021) and 26 weeks (P=.021) and there was a tendency for improved walking speed in the RELOAD group at 26 weeks (P=.068). There were no between-group differences in knee extension moment during the FTSST. Surgical-limb knee extension moments during walking increased from baseline to 26 weeks in the RELOAD group and decreased in the CONTROL group (P=.008). CONCLUSION WB biofeedback training had no effect on functional WB symmetry or knee extension moments during the FTSST. However, the biofeedback training resulted in increases of knee extension moments during gait and improved FTSST times. LEVEL OF EVIDENCE Therapy, level 2b. PMID:26207975

  20. The mechanical consequences of load bearing in the equine third metacarpal across speed and gait: the nonuniform distributions of normal strain, shear strain, and strain energy density

    PubMed Central

    Rubin, Clinton T.; Seeherman, Howard; Qin, Yi-Xian; Gross, Ted S.

    2013-01-01

    Distributions of normal strain, shear strain, and strain energy density (SED) were determined across the midshaft of the third metacarpal (MCIII, or cannon bone) of 3 adult thoroughbred horses as a function of speed and gait. A complete characterization of the mechanical demands of the bone made through the stride and from mild through the extremes of locomotion was possible by using three 3-element rosette strain gauges bonded at the diaphyseal midshaft of the MCIII and evaluating the strain output with beam theory and finite element analysis. Mean ± sd values of normal strain, shear strain, and SED increased with speed and peaked during a canter (−3560±380 microstrain, 1760±470 microstrain, and 119±23 kPa, respectively). While the location of these peaks was similar across animals and gaits, the resulting strain distributions across the cortex were consistently nonuniform, establishing between a 73-fold (slow trot) to a 330-fold (canter) disparity between the sites of maximum and minimum SED for each gait cycle. Using strain power density as an estimate of strain history across the bone revealed a 154-fold disparity between peak and minimum at the walk but fell to ∼32-fold at the canter. The nonuniform, minimally varying, strain environment suggests either that bone homeostasis is mediated by magnitude-independent mechanical signals or that the duration of stimuli necessary to establish and maintain tissue integrity is relatively brief, and thus the vast majority of strain information is disregarded.—Rubin, C. T., Seeherman, H., Qin, Y.-X., Gross, T. S., The mechanical consequences of load bearing in the equine third metacarpal across speed and gait: the nonuniform distributions of normal strain, shear strain, and strain energy density. PMID:23355269

  1. Neonatal Biomarkers of Inflammation: Correlates of Early Neurodevelopment and Gait in Very-Low-Birth-Weight Preterm Children.

    PubMed

    Rose, Jessica; Vassar, Rachel; Cahill-Rowley, Katelyn; Hintz, Susan R; Stevenson, David K

    2016-01-01

    Objective Neonatal biomarkers of inflammation were examined in relation to early neurodevelopment and gait in very-low-birth-weight (VLBW) preterm children. We hypothesized that preterm infants exposed to higher levels of neonatal inflammation would demonstrate lower scores on Bayley Scales of Infant Toddler Development, 3rd ed. (BSID-III) and slower gait velocity at 18 to 22 months adjusted age. Study Design A total of 102 VLBW preterm infants (birthweight [BW] ≤ 1,500 g, gestational age [GA] ≤ 32 weeks) admitted to neonatal intensive care unit [NICU] were recruited. Neonatal risk factors examined were GA at birth, BW, bronchopulmonary dysplasia, necrotizing enterocolitis, retinopathy of prematurity, sepsis, and serum C-reactive protein (CRP), albumin, and total bilirubin over first 2 postnatal weeks. At 18 to 22 months, neurodevelopment was assessed with BSID-III and gait was assessed with an instrumented mat. Results Children with neonatal CRP ≥ 0.20 mg/dL (n = 52) versus < 0.20 mg/dL (n = 37) had significantly lower BSID-III composite cognitive (92.0 ± 13.1 vs. 100.1 ± 9.6, p = 0.002), language (83.9 ± 16.0 vs. 95.8 ± 14.2, p < 0.001), and motor scores (90.0 ± 13.2 vs. 98.8 ± 10.1, p = 0.002), and slower gait velocity (84.9 ± 19.0 vs. 98.0 ± 22.4 cm/s, p = 0.004). Higher neonatal CRP correlated with lower cognitive (rho =  - 0.327, p = 0.002), language (rho =  - 0.285, p = 0.007), and motor scores (rho =  - 0.257, p = 0.015), and slower gait (rho =  - 0.298, p = 0.008). Multivariate analysis demonstrated neonatal CRP ≥ 0.20 mg/dL significantly predicted BSID-III cognitive (adjusted R(2) = 0.104, p = 0.008), language (adjusted R(2) = 0.124, p = 0.001), and motor scores (adjusted R(2) = 0.122, p = 0.004). Conclusions Associations between low-level neonatal inflammation and neurodevelopment suggest early biomarkers that may inform neuroprotective treatment for preterm children. PMID:26212060

  2. Development of a compact, light weight magnetic bearing

    NASA Technical Reports Server (NTRS)

    Meeks, Crawford; Dirusso, Eliseo; Brown, Gerald V.

    1990-01-01

    A compact, lightweight radial-load bearing has been devised with permanent magnet bias and actively controlled radial loading. The novel design uses permanent magnets to generate a coaxial magnetic field that energizes two radial air gaps. Two electromechanical stators modulate the airgap field in order to impart stability and control. Attention is given to the implementation of this design in an application involving operation at ambient and cryogenic temperatures at loads of up to 500 lbs. Stiffnesses of up to 17,500 N/mm have been obtained.

  3. The Effect of Body Weight Support Treadmill Training on Gait Recovery, Proximal Lower Limb Motor Pattern, and Balance in Patients with Subacute Stroke

    PubMed Central

    Mao, Yu-Rong; Lo, Wai Leung; Lin, Qiang; Li, Le; Xiao, Xiang; Raghavan, Preeti; Huang, Dong-Feng

    2015-01-01

    Objective. Gait performance is an indicator of mobility impairment after stroke. This study evaluated changes in balance, lower extremity motor function, and spatiotemporal gait parameters after receiving body weight supported treadmill training (BWSTT) and conventional overground walking training (CT) in patients with subacute stroke using 3D motion analysis. Setting. Inpatient department of rehabilitation medicine at a university-affiliated hospital. Participants. 24 subjects with unilateral hemiplegia in the subacute stage were randomized to the BWSTT (n = 12) and CT (n = 12) groups. Parameters were compared between the two groups. Data from twelve age matched healthy subjects were recorded as reference. Interventions. Patients received gait training with BWSTT or CT for an average of 30 minutes/day, 5 days/week, for 3 weeks. Main Outcome Measures. Balance was measured by the Brunel balance assessment. Lower extremity motor function was evaluated by the Fugl-Meyer assessment scale. Kinematic data were collected and analyzed using a gait capture system before and after the interventions. Results. Both groups improved on balance and lower extremity motor function measures (P < 0.05), with no significant difference between the two groups after intervention. However, kinematic data were significantly improved (P < 0.05) after BWSTT but not after CT. Maximum hip extension and flexion angles were significantly improved (P < 0.05) for the BWSTT group during the stance and swing phases compared to baseline. Conclusion. In subacute patients with stroke, BWSTT can lead to improved gait quality when compared with conventional gait training. Both methods can improve balance and motor function. PMID:26649295

  4. Effects of robot-assisted gait training on the balance and gait of chronic stroke patients: focus on dependent ambulators

    PubMed Central

    Cho, Duk Youn; Park, Si-Woon; Lee, Min Jin; Park, Dae Sung; Kim, Eun Joo

    2015-01-01

    [Purpose] The purpose of this study was to confirm the effect of robot-assisted gait training on the balance and gait ability of stroke patients who were dependent ambulators. [Subjects and Methods] Twenty stroke patients participated in this study. The participants were allocated to either group 1, which received robot-assisted gait training for 4 weeks followed by conventional physical therapy for 4 weeks, or group 2, which received the same treatments in the reverse order. Robot-assisted gait training was conducted for 30 min, 3 times a week for 4 weeks. The Berg Balance Scale, Modified Functional Reach Test, Functional Ambulation Category, Modified Ashworth Scale, Fugl-Meyer Assessment, Motricity Index, and Modified Barthel Index were assessed before and after treatment. To confirm the characteristics of patients who showed a significant increase in Berg Balance Scale after robot-assisted gait training as compared with physical therapy, subgroup analysis was conducted. [Results] Only lateral reaching and the Functional Ambulation Category were significantly increased following robot-assisted gait training. Subscale analyses identified 3 patient subgroups that responded well to robot-assisted gait training: a subgroup with hemiplegia, a subgroup in which the guidance force needed to be decreased to needed to be decreased to ≤45%, and a subgroup in which weight bearing was decreased to ≤21%. [Conclusion] The present study showed that robot-assisted gait training is not only effective in improving balance and gait performance but also improves trunk balance and motor skills required by high-severity stroke patients to perform activities daily living. Moreover, subscale analyses identified subgroups that responded well to robot-assisted gait training. PMID:26644642

  5. When Should Open Reduction and Internal Fixation Ankle Fractures Begin Weight Bearing? A Systematic Review.

    PubMed

    Smith, Toby O; Davies, Leigh

    2008-02-01

    The objective of this paper was to review the literature to assess when open reduction and internal fixation ankle fractures should commence weight bearing for the best outcome. An electronic search was undertaken of the databases AMED, Cinahl, Embase, Medline (via Ovid), Pedro and Pubmed, from their inception to November 2005. References lists were scrutinised and a hand search was also performed. We included all English language, human subject, controlled clinical trials, comparing the effects of early against later weight bearing following open reduction and internal fixation of ankle fractures. Two reviewers independently assessed the methodological quality of the literature using the PEDro (Physiotherapy Evidence Database) scoring system. Five papers comprising of 366 ankle fractures were reviewed. Overall, there was no significant difference between commencing early, compared to later weight bearing in subjects following open reduction and internal fixation, when evaluated against function, pain, range of movement, radiological assessment, complications, and return to work. The evidence reviewed was generally poor, with numerous methodological design limitations. The literature suggested that were was little difference between encouraging early or delayed weight bearing after open reduction and internal fixation of ankle fractures. Neither early nor later weight bearing significantly improves or jeopardises outcomes. However, due to the plethora of methodological limitations and limited evidence, it is not possible to reference this conclusion with conviction. Further large, well-designed randomized controlled trials are required to evaluate this area. PMID:26815494

  6. Anterior cruciate ligament strain and tensile forces for weight-bearing and non-weight-bearing exercises: a guide to exercise selection.

    PubMed

    Escamilla, Rafael F; Macleod, Toran D; Wilk, Kevin E; Paulos, Lonnie; Andrews, James R

    2012-03-01

    There is a growing body of evidence documenting loads applied to the anterior cruciate ligament (ACL) for weight-bearing and non-weight-bearing exercises. ACL loading has been quantified by inverse dynamics techniques that measure anterior shear force at the tibiofemoral joint (net force primarily restrained by the ACL), ACL strain (defined as change in ACL length with respect to original length and expressed as a percentage) measured directly in vivo, and ACL tensile force estimated through mathematical modeling and computer optimization techniques. A review of the biomechanical literature indicates the following: ACL loading is generally greater with non-weight-bearing compared to weight-bearing exercises; with both types of exercises, the ACL is loaded to a greater extent between 10° to 50° of knee flexion (generally peaking between 10° and 30°) compared to 50° to 100° of knee flexion; and loads on the ACL change according to exercise technique (such as trunk position). Squatting with excessive forward movement of the knees beyond the toes and with the heels off the ground tends to increase ACL loading. Squatting and lunging with a forward trunk tilt tend to decrease ACL loading, likely due to increased hamstrings activity. During seated knee extension, ACL force decreases when the resistance pad is positioned more proximal on the anterior aspect of the lower leg, away from the ankle. The evidence reviewed as part of this manuscript provides objective data by which to rank exercises based on loading applied to the ACL. The biggest challenge in exercise selection post-ACL reconstruction is the limited knowledge of the optimal amount of stress that should be applied to the ACL graft as it goes through its initial incorporation and eventual maturation process. Clinicians may utilize this review as a guide to exercise selection and rehabilitation progression for patients post-ACL reconstruction. PMID:22387600

  7. Delayed healing of a navicular stress fracture, following limited weight-bearing activity

    PubMed Central

    Robinson, Matthew; Fulcher, Mark

    2014-01-01

    This report describes a 21-year-old man, a semiprofessional football (soccer) player, with a navicular stress fracture. It highlights the difficulty in diagnosing the condition and the complications arising from inadequate management. The case discusses the optimal management of these stress fractures and the detrimental role of weight-bearing recovery. The diagnosis of navicular stress fractures is challenging, and a high index of suspicion is required. The available literature indicates that limited weightbearing is not an appropriate treatment for navicular stress injuries. Non-weight-bearing (NWB) cast immobilisation for 6–8 weeks appears to be the gold standard treatment; however, open reduction with internal fixation (ORIF) has similar success rates and an equal return-to-play time but should also be followed by a period of NWB. NWB cast immobilisation for 6 weeks remains a good second option at any time following failed limited weight-bearing activity. PMID:24618870

  8. Tibial torque generation in a flexed weight-bearing stance.

    PubMed

    Shoemaker, S C; Markolf, K L; Dorey, F J; Zager, S; Namba, R

    1988-03-01

    Internal and external torque generated about the long axis of the lower extremity was measured in 18 male subjects who were instructed to twist with maximal effort against a fixed footplate containing an instrumented torque cell. Mean torque values ranged from 30 to 71 newton meters (Nm) depending upon the test conditions. Torques recorded during the flexed single-leg stance were 19% to 49% higher than those measured while seated. Values at 45 degrees of knee flexion were 11% to 16% greater than those at 20 degrees. Torques generated while wearing a ski boot were 8% to 11% greater than those recorded in an athletic shoe. When movement of the pelvis and upper torso was allowed, torque values were 17% to 49% higher than those recorded when the hips and shoulders were restrained which allowed only lower leg musculature to act in an isolated fashion. There were no differences between internal versus external generated torques when the hips and torso were restrained. When the hips and shoulders were unrestrained, internal torque was 12% greater than external torque. There were no strong correlations between generated torque and body weight or height. These generated torque values suggest that if ski bindings are set to American Society for Testing and Materials (ASTM) standards for twist-release torque, then upper torso and pelvic movement in conjunction with tensed knee musculature (i.e., a "locked knee") may be necessary to accomplish binding release. Use of the lower leg musculature alone (i.e., ankle twist) may not generate sufficient torque for release. PMID:3342561

  9. Osteoporosis Knowledge, Calcium Intake, and Weight-Bearing Physical Activity in Three Age Groups of Women.

    ERIC Educational Resources Information Center

    Terrio, Kate; Auld, Garry W.

    2002-01-01

    Determined the extent and integration of osteoporosis knowledge in three age groups of women, comparing knowledge to calcium intake and weight bearing physical activity (WBPA). Overall calcium intake was relatively high. There were no differences in knowledge, calcium intake, or WBPA by age, nor did knowledge predict calcium intake and WBPA. None…

  10. Osteoporosis Knowledge, Calcium Intake, and Weight-Bearing Physical Activity in Three Age Groups of Women.

    ERIC Educational Resources Information Center

    Terrio, Kate; Auld, Garry W.

    2002-01-01

    Determined the extent and integration of osteoporosis knowledge in three age groups of women, comparing knowledge to calcium intake and weight bearing physical activity (WBPA). Overall calcium intake was relatively high. There were no differences in knowledge, calcium intake, or WBPA by age, nor did knowledge predict calcium intake and WBPA. None

  11. Walking assistance apparatus using a spatial parallel link mechanism and a weight bearing lift.

    PubMed

    Tanaka, Eiichirou; Ikehara, Tadaaki; Sato, Yusuke; Yusa, Hirokazu; Sakurai, Tomohiro; Saegusa, Shozo; Ito, Kazuhisa; Yuge, Louis

    2011-01-01

    A prototype for a walking assistance apparatus for the elderly or motor palsy patients was developed as a next-generation vehicle or movable neuro-rehabilitation training appliance, using a novel spatial parallel link mechanism and a bearing lift. The flat steps of the apparatus move in parallel with the ground; the apparatus can support entire leg alignment (including soles) and assist; walking behavior at ankle, knee and hip joints simultaneously. In order to respond the variation of equipped person's walking velocity, the length of stride and walking cycle while walking with wearing the apparatus were compensated by using the relation of walking ratio. Therefore the apparatus can be controlled in response to equipped person's will. Motor palsy and muscle weakness patients can walk by themselves by using the apparatus; patients who have ambulation difficulty can use the apparatus with weight bearing lift that we developed. Using the apparatus with the weight bearing lift prevents stumbling and enables input of walking movement to the brain motor area. It is very effective for rehabilitation to use the apparatus with the weight bearing lift. This newly developed system facilitates motor palsy and muscle weakness patients in the rehabilitation program. PMID:22275667

  12. Short communication: Estimation of genetic parameters for gait in Canadian Holstein cows.

    PubMed

    Chapinal, N; Sewalem, A; Miglior, F

    2012-12-01

    Lameness is one of the most important welfare and economic problems in modern dairy herds. In addition to environmental factors, lameness is affected by genetics and thus, long-term improvement of lameness can be accomplished through genetic selection. The objective of the study was to estimate the genetic parameters of a validated gait score and specific gait attributes for Holstein cows from a university dairy research herd. Two hundred thirty-three cows were gait scored multiple times over time (n=1,664 records) in different experiments using a 1-to-5 numerical rating system (NRS). One hundred seventy-two cows (n=657 records) also had 6 gait attributes scored using a 100-unit continuous visual analog scale (back arch, head bob, tracking up, joint flexion, asymmetric gait, and reluctance to bear weight). Single-trait linear animal models were used to estimate the heritability of NRS and each gait attribute, whereas a multivariate linear animal model was used to estimate genetic correlations between traits. The NRS and the gait attributes deteriorated with parity, and the scores for NRS, back arch, joint flexion, and asymmetry of the steps increased rapidly in early lactation. The heritability estimate (±SE) for NRS was 0.09±0.09. Four of the gait attributes (reluctance to bear weight, head bob, tracking up, and asymmetry of the steps) had higher heritability than NRS, ranging from 0.11±0.13 to 0.42±0.15, whereas back arch showed no genetic variation. However, the small sample of animals resulted in large standard error of the estimates. The genetic correlations between NRS and the gait attributes were >0.70, whereas the genetic correlations among the different gait attributes ranged from 0.14 to 0.92. In conclusion, NRS and most gait attributes showed genetic variation, indicating the opportunity to improve gait through genetic selection. Some specific gait attributes were more heritable than NRS and were genetically correlated with NRS. Further research with a larger population is needed to assess whether specific gait attributes would be suitable candidate traits to consider in genetic evaluations in the future. PMID:23063149

  13. Periprosthetic bone mineral density and fixation of the uncemented CLS stem related to different weight bearing regimes

    PubMed Central

    Mattsson, Per; Milbrink, Jan; Larsson, Sune; Mallmin, Hans

    2010-01-01

    Background and purpose There is no consensus on the best rehabilitation regime after uncemented total hip arthroplasty. Theoretically, bone ingrowth into the implant should benefit from initial partial weight bearing. We investigated whether the degree of postoperative weight bearing influences the periprosthetic bone mineral density (BMD) and/or the stability of the CLS stem. Patients and methods 38 patients received an uncemented CLS stem and were randomized to either unrestricted postoperative weight bearing or to partial weight bearing for 3 months. Periprosthetic BMD was measured in the 7 Gruen zones with DXA and the stability of the femoral stem was assessed by radiostereometric analysis (RSA) after surgery and at 3, 12, 24, and 60 months. Results Periprosthetic BMD was not influenced by the type of postoperative weight bearing. BMD was reduced by 8–15% in all Gruen zones at 3 months. Restoration toward initial BMD was observed in all zones except in zone 7 (calcar region), where BMD was reduced by 22% at 5 years. Immediate weight bearing after surgery had no influence on the stability of the CLS stem, as assessed by RSA. Interpretation Immediate full weight bearing after uncemented total hip arthroplasty is safe. There is no difference in the periprosthetic BMD or in stability of the stem as measured by RSA compared to partial weight bearing for 3 months. BMD is reduced by more than 20% in the calcar region around a CLS stem after 5 years. PMID:20446828

  14. Simple kinematic gait measurements.

    PubMed

    Bajd, T; Kralj, A

    1980-04-01

    Simple kinematic gait measurement equipment was developed providing fast and inexpensive clinical gait analysis. Such a simple system can be used as a stand-alone clinical gait analyser, or as an accessory for measurements whose results are not sufficiently weighted statistically, such as TV, Selspot, force plate. Time, distance and velocity parameters are included in the clinical gait analysis. Time parameters (step and stride time, swing and stance phase) are measured via easily attachable foot-switches. Analog and digital versions were developed to analyse distance (stride and step length) and velocity (instantaneous velocity of centre of gravity) parameters. With the analog device the velocity is measured by tachometer and distance by potentiometer, while using digital methods, both parameters can be obtained from an optical transducer. PMID:7374117

  15. Recovery of lower limb function following 6 weeks of non-weight bearing

    NASA Astrophysics Data System (ADS)

    MacIntyre, Donna L.; Eng, Janice J.; Allen, Trevor J.

    2005-05-01

    Skeletal muscle weakness and atrophy occur following an extended period of decreased use, including space flight and limb unloading. It is also likely that affected muscles will be susceptible to a re-loading injury when they begin return to earth or weight bearing. However, there is a paucity of literature evaluating the response of human unloaded muscle to exercise and return to activity. The purpose of this pilot study was to evaluate the soreness, function and strength response of muscle to re-loading in seven patients who were non-weight bearing for 6 weeks, compared to five healthy subjects. Function improved significantly over time for the patients but was still less than the healthy subjects over 12 weeks of physiotherapy. Concentric quadriceps muscle strength increased significantly over time for the patients. There was considerable variability in the patients' reports of muscle soreness but there were no significant changes over time or between groups.

  16. Functional Comparison of Immediate and Late Weight Bearing after Ankle Bimalleolar Fracture Surgery

    PubMed Central

    Ağır, İsmail; Tunçer, Nejat; Küçükdurmaz, Fatih; Gümüstaş, Seyitali; Akgül, Esra Demirel; Akpinar, Fuat

    2015-01-01

    Aim : The aim of the study is to compare immediate weight bearing with below-knee cast or immobilization with plaster splint in 6 weeks in patients after operative treatment for ankle bimalleolar fractures. Methods : Fifty-three patients with ankle bimalleolar fractures were treated operatively in 2005 to 2010 and then were randomly allocated to two groups. Immediately weight bearing in a below-knee cast (26 patients) and immobilization in a plaster splint for the first six postoperative weeks (27 patients). A mean age 37.9 (min 17; max 72). An average follow-up 26.1 months. (min 14; max 55). All fractures were classified with Lauge-Hansen classification. Functional results of both groups were evaluated with AOFAS for the postoperative one year after surgical treatment. Results : According to the AOFAS scoring system, results were excellent and good in 17 patients in group 1. On the other hand, results were excellent and good in 14 patients in group 2. Conclusion : As a result we think that weight bearing protocol should be advantaged for patients with ankle bimalleolar fractures after surgical treatment immediately. PMID:26069513

  17. Electromyography activity of the deltoid muscle of the weight-bearing side during shoulder flexion in various weight-bearing positions

    PubMed Central

    Ju, Sung-kwang; Yoo, Won-gyu

    2015-01-01

    [Purpose] This study investigated the deltoid muscle activation during shoulder flexion exercise in various weight-bearing positions. [Subjects] A total of 15 males participated. [Methods] The participants completed three repetitions of shoulder flexion exercises in three positions (prone-on-elbow, quadruped, and standing) with electromyography activity being collected from the exercised. The muscle activations in each position by each exercise were compared using a one-way analysis of variance. [Results] The electromyography activities of the middle and posterior deltoids differed significantly among positions. The prone-on-elbow and quadruped position showed a significantly higher activity than the standing position. There were no significant differences between the prone-on-elbow and quadruped positions. [Conclusion] The deltoid muscles were further strengthened in the low posture positions (prone-on-elbows and quadruped) than in standing. PMID:26644694

  18. Electromyography activity of the deltoid muscle of the weight-bearing side during shoulder flexion in various weight-bearing positions.

    PubMed

    Ju, Sung-Kwang; Yoo, Won-Gyu

    2015-10-01

    [Purpose] This study investigated the deltoid muscle activation during shoulder flexion exercise in various weight-bearing positions. [Subjects] A total of 15 males participated. [Methods] The participants completed three repetitions of shoulder flexion exercises in three positions (prone-on-elbow, quadruped, and standing) with electromyography activity being collected from the exercised. The muscle activations in each position by each exercise were compared using a one-way analysis of variance. [Results] The electromyography activities of the middle and posterior deltoids differed significantly among positions. The prone-on-elbow and quadruped position showed a significantly higher activity than the standing position. There were no significant differences between the prone-on-elbow and quadruped positions. [Conclusion] The deltoid muscles were further strengthened in the low posture positions (prone-on-elbows and quadruped) than in standing. PMID:26644694

  19. A prospective study comparing attempted weight bearing in fiberglass below-knee casts and prefabricated pneumatic braces.

    PubMed

    Mason, Lyndon W; Dodds, Alex

    2010-04-01

    Partial weight bearing is commonly advised after fracture of the lower extremity. Research has determined this to be inaccurate both in its instruction and its reproducibility. Many trauma departments are commonly using alternatives to plaster in the splintage of fractures, such as fiberglass and the prefabricated pneumatic braces. This study's null hypothesis is that there is no difference between partial weight bearing through a fiberglass cast as compared with a pneumatic walker. A prospective study was conducted in our department including all patients who had metatarsal or ankle fractures and could partially weight bear. Patients were excluded if they were not allowed to bear weight, had received operative fixation of their fracture, or were younger than age 16 years. The patients' total weight was measured first, and then they were trained to place 50% of their weight through the splinted limb. Three measurements were taken of their attempted weight bearing at 50%, and they were blinded to the results. Over a 16-month period, 117 patients were enrolled for this study: 72 in the pneumatic walker group and 45 in the fiberglass group. There was no significant difference in sex, age, or fracture type. There was a significant difference in percentage of weight placed through the splinted limb, with the pneumatic brace group placing much greater force than the fiberglass group. This may have been caused by altered proprioception from the walker. It is important to realize this when prescribing partial weight bearing in a particular splint as this may result in avoidable complications. PMID:20400414

  20. [Normal gait and its changes after total arthroplasty of the lower extremity. Study on 200 subjects of the support phase of the step and its impulse].

    PubMed

    Lord, G; Gentaz, R; Gandolfi, R

    1977-01-01

    The authors have studied the normal gait of 50 individuals using a dynamometric platform. Measurements have been made of the impulse at each step, the weight bearing phase and the forces transmitted by the foot to the floor. The results have been compared with those obtained from a study of the gait of 150 patients treated by total prostheses (133 hips, 10 knees, 7 ankles). This type of study leads to a better appreciation of operative results. PMID:143007

  1. In Vivo Kinematics of the Knee during Weight Bearing in High Flexion

    PubMed Central

    Qi, Wei; Hosseini, Ali; Tsai, Tsung-Yuan; Li, Jing-Sheng; Rubash, Harry E.; Li, Guoan

    2013-01-01

    Achieving high flexion is an objective of contemporary total knee arthoplasty, however little is known on the knee biomechanics at high flexion under weight-bearing conditions. This study is to investigate the 6DOF kinematics and tibiofemoral cartilage contact biomechanics of the knee during weight-bearing flexion from full extension to maximal flexion. Eight knees from seven healthy subjects with no history of injuries or chronic pain were recruited. The knees were MRI scanned to create 3D models of the tibia and femur, including their articular cartilage surfaces. The subjects were then imaged using a dual fluoroscopic image system while performing a weight-bearing quasi-static single-legged lunge from full extension to maximal flexion. The 6DOF kinematics and the articular cartilage contact locations were measured along the flexion path of the knee. The result indicated that the internal tibial rotation increased sharply at low flexion angles (full extension to 30°), maintained a small variation in the middle range of flexion (30° to 120°), and then sharply increased again at high flexion angles (120° to maximal flexion). The contact point moved similarly in the medial and lateral compartments before 120° of flexion, but less on the medial compartment at high flexion angles. The results indicated that the knee motion couldn’t be described using one character in the entire range of flexion, especially in high flexion. The knee kinematic data in the entire range of flexion of the knee could be instrumental for designing new knee prostheses to achieve physical high flexion and improving rehabilitation protocols after knee injuries. PMID:23591448

  2. In vivo kinematics of the knee during weight bearing high flexion.

    PubMed

    Qi, Wei; Hosseini, Ali; Tsai, Tsung-Yuan; Li, Jing-Sheng; Rubash, Harry E; Li, Guoan

    2013-05-31

    Achieving high flexion is an objective of contemporary total knee arthoplasty; however little is known on the knee biomechanics at high flexion under weight-bearing conditions. This study investigates the 6DOF kinematics and tibiofemoral cartilage contact biomechanics of the knee during weight-bearing flexion from full extension to maximal flexion. Eight knees from seven healthy subjects with no history of injuries or chronic pain were recruited. The knees were MRI scanned to create 3D models of the tibia and femur, including their articular cartilage surfaces. The subjects were then imaged using a dual fluoroscopic image system while performing a weight-bearing quasi-static single-legged lunge from full extension to maximal flexion. The 6DOF kinematics and the articular cartilage contact locations were measured along the flexion path of the knee. The result indicated that the internal tibial rotation increased sharply at low flexion angles (full extension to 30°), maintained a small variation in the middle range of flexion (30-120°, and then sharply increased again at high flexion angles (120° to maximal flexion). The contact point moved similarly in the medial and lateral compartments before 120° of flexion, but less on the medial compartment at high flexion angles. The results indicated that the knee motion could not be described using one character in the entire range of flexion, especially in high flexion. The knee kinematic data in the entire range of flexion of the knee could be instrumental for designing new knee prostheses to achieve physical high flexion and improving rehabilitation protocols after knee injuries. PMID:23591448

  3. Evaluation of Dynamic Weight Bearing for Measuring Nonevoked Inflammatory Hyperalgesia in Mice

    PubMed Central

    Griffioen, Mari A.; Dernetz, Valerie H.; Yang, Gee Su; Griffith, Kathleen A.; Dorsey, Susan G.; Renn, Cynthia L.

    2014-01-01

    Background Animal models in pain research have suggested that inclusion of both evoked and nonevoked behavioral measures are needed to better reflect the human pain experience. Individuals with chronic pain are known to experience spontaneous pain, in addition to pain, following exposure to an external stimulus. Recently, the Dynamic Weight Bearing (DWB) apparatus was developed to assess for nonevoked hyperalgesia by capturing weight bearing and surface distribution in the paws of mice following acute inflammation. Objectives The aim of this study was to evaluate the DWB test as a measure of nonevoked hyperalgesia. Method The experimental group received an intraplantar injection to the left hind paw of the inflammatory agent—Complete Freund's Adjuvant (CFA)—while the vehicle control group received a saline injection, and the naïve control group had no treatment. Caliper and plethysmometer were used to verify inflammation, and the hot-plate test was used as a measure for stimulus evoked hyperalgesia. Data were collected at baseline, three hours, one, three, and seven days after injection. Results Mice injected with CFA showed a statistically significant higher mean paw thickness and volume displacement compared to vehicle and naïve control groups. In the hot-plate testing, CFA-treated mice showed lower response temperature at seven days compared to other groups. On the DWB test, CFA-treated mice showed a reduction in the ipsilateral paw load and surface area compared to the contralateral paw load at Day 1, Day 3 and Day 7. Discussion Mice with inflammation demonstrated alterations in weight bearing, as well as increased thermal hyperalgesia in comparison to controls groups. These findings support the use of the DWB test as a tool for measuring nonevoked inflammatory hyperalgesia in a mouse model. PMID:25738619

  4. [Disruption of anterointernal weight bearing: sequelae of surgical treatment of hallux valgus].

    PubMed

    García-Renedo, R J; Carranza-Bencano, A; Delgado-Calle, J; Núñez-Samper, M; Llanos-Alcázar, L F

    2012-01-01

    Sequelae of forefoot surgery range between 30 and 40%; the most frequent ones are transfer metatarsalgia and deformity relapse. Forefoot surgery complications disrupt biomechanics. Anterointernal weight bearing alteration is most frequent, due to involvement of the metatarsal, the phalanx or both. Metatarsophalangeal arthrodesis normalizes the length of the first ray and pressure transmission. The use of this technique has made it possible to confirm pain relief, as well as improved function and a better cosmetic result, which allows the patient to wear ormal footwear. PMID:24712209

  5. Alterations of collagen matrix in weight-bearing bones during skeletal unloading

    NASA Technical Reports Server (NTRS)

    Shiiba, M.; Arnaud, S. B.; Tanzawa, H.; Uzawa, K.; Yamauchi, M.

    2001-01-01

    Skeletal unloading induces loss of bone mineral density in weight-bearing bones. The objectives of this study were to characterize the post-translational modifications of collagen of weight-bearing bones subjected to hindlimb unloading for 8 weeks. In unloaded bones, tibiae and femurs, while the overall amino acid composition was essentially identical in the unloaded and control tibiae and femurs, the collagen cross-link profile showed significant differences. Two major reducible cross-links (analyzed as dihydroxylysinonorleucine and hydroxylysinonorleucine) were increased in the unloaded bones. In addition, the ratios of the former to the latter as well as pyridinoline to deoxypyridinoline were significantly decreased in the unloaded bones indicating a difference in the extent of lysine hydroxylation at the cross-linking sites between these two groups. These results indicate that upon skeletal unloading the relative pool of newly synthesized collagen is increased and it is post-translationally altered. The alteration could be associated with impaired osteoblastic differentiation induced by skeletal unloading that results in a mineralization defect.

  6. A Canine Non-Weight-Bearing Model with Radial Neurectomy for Rotator Cuff Repair

    PubMed Central

    Ji, Xiaoxi; Bao, Nirong; An, Kai-Nan; Amadio, Peter C.; Steinmann, Scott P.; Zhao, Chunfeng

    2015-01-01

    Background The major concern of using a large animal model to study rotator cuff repair is the high rate of repair retears. The purpose of this study was to test a non-weight-bearing (NWB) canine model for rotator cuff repair research. Methods First, in the in vitro study, 18 shoulders were randomized to 3 groups. 1) Full-width transections repaired with modified Mason-Allen sutures using 3-0 polyglactin suture, 2) Group 1 repaired using number 2 (#2) polyester braid and long-chain polyethylene suture, and 3) Partial-width transections leaving the superior 2 mm infraspinatus tendon intact without repair. In the in vivo study of 6 dogs, the infraspinatus tendon was partially transected as the same as the in vitro group 3. A radial neurectomy was performed to prevent weight bearing. The operated limb was slung in a custom-made jacket for 6 weeks. Results In the in vitro study, mean ultimate tensile load and stiffness in Group 2 were significantly higher than Group 1 and 3 (p<0.05). In the in vivo study, gross inspection and histology showed that the preserved superior 2-mm portion of the infraspinatus tendon remained intact with normal structure. Conclusions Based on the biomechanical and histological findings, this canine NWB model may be an appropriate and useful model for studies of rotator cuff repair. PMID:26107616

  7. Biomechanical effects of lateral and medial wedge insoles on unilateral weight bearing

    PubMed Central

    Sawada, Tomonori; Kito, Nobuhiro; Yukimune, Masaki; Tokuda, Kazuki; Tanimoto, Kenji; Anan, Masaya; Takahashi, Makoto; Shinkoda, Koichi

    2016-01-01

    [Purpose] Lateral wedge insoles reduce the peak external knee adduction moment and are advocated for patients with knee osteoarthritis. However, some patients demonstrate adverse biomechanical effects with treatment. In this study, we examined the immediate effects of lateral and medial wedge insoles under unilateral weight bearing. [Subjects and Methods] Thirty healthy young adults participated in this study. The subjects were assessed by using the foot posture index, and were divided into three groups: normal foot, pronated foot, and supinated foot groups. The knee adduction moment and knee-ground reaction force lever arm under the studied conditions were measured by using a three-dimensional motion capture system and force plates. [Results] In the normal and pronated groups, the change in knee adduction moment significantly decreased under the lateral wedge insole condition compared with the medial wedge insole condition. In the normal group, the change in the knee-ground reaction force lever arm also significantly decreased under the lateral wedge insole condition than under the medial wedge insole condition. [Conclusion] Lateral wedge insoles significantly reduced the knee adduction moment and knee-ground reaction force lever arm during unilateral weight bearing in subjects with normal feet, and the biomechanical effects varied according to individual foot alignment. PMID:26957775

  8. Biomechanical effects of lateral and medial wedge insoles on unilateral weight bearing.

    PubMed

    Sawada, Tomonori; Kito, Nobuhiro; Yukimune, Masaki; Tokuda, Kazuki; Tanimoto, Kenji; Anan, Masaya; Takahashi, Makoto; Shinkoda, Koichi

    2016-01-01

    [Purpose] Lateral wedge insoles reduce the peak external knee adduction moment and are advocated for patients with knee osteoarthritis. However, some patients demonstrate adverse biomechanical effects with treatment. In this study, we examined the immediate effects of lateral and medial wedge insoles under unilateral weight bearing. [Subjects and Methods] Thirty healthy young adults participated in this study. The subjects were assessed by using the foot posture index, and were divided into three groups: normal foot, pronated foot, and supinated foot groups. The knee adduction moment and knee-ground reaction force lever arm under the studied conditions were measured by using a three-dimensional motion capture system and force plates. [Results] In the normal and pronated groups, the change in knee adduction moment significantly decreased under the lateral wedge insole condition compared with the medial wedge insole condition. In the normal group, the change in the knee-ground reaction force lever arm also significantly decreased under the lateral wedge insole condition than under the medial wedge insole condition. [Conclusion] Lateral wedge insoles significantly reduced the knee adduction moment and knee-ground reaction force lever arm during unilateral weight bearing in subjects with normal feet, and the biomechanical effects varied according to individual foot alignment. PMID:26957775

  9. Effects of feedback on activation of the quadriceps during weight-bearing tasks of the Wii.

    PubMed

    Fernandes da Silva, Fabiano; Aparecido de Souza, Renato; Dias, Eric Fernandes; Silveira, Landulfo; Villaverde, Antonio Balbin

    2015-06-01

    [Purpose] This investigation evaluated the effect of real-time feedback on electrical activation of the quadriceps during 3 weight-bearing tasks of the Wii Fit Plus(). [Subjects] Thirty male healthy volunteers were recruited. [Methods] Activation of the vastus medialis, vastus lateralis, and rectus femoris muscles was recorded during virtual lunge, single leg extension, and single leg reach exercises. Each exercise was performed twice in 3 randomized experimental conditions (with visual feedback, with auditory feedback, and with no feedback). The normalized electromyographic data (using maximum voluntary isometric contraction) were analyzed using repeated measures analysis of variance and Tukey's test. [Results] No significant difference was found in the muscles among the feedback conditions during the 3 exercises. However, the variation in the muscle activity of the vastus medialis and vastus lateralis (18.23-29.20% of maximum voluntary isometric contraction) was higher (47-62%) than that in the rectus femoris (7.35-12.98% of maximum voluntary isometric contraction). [Conclusion] Real-time feedback did not alter quadriceps activation during the Wii tasks. Additionally, these games showed electromyographic activation levels similar to those for the same tasks outside the virtual environment. The Wii weight-bearing tasks could therefore constitute a physical activity program but without the additional benefit of feedback. PMID:26180301

  10. Effects of immobilization on rat hind limb muscles under non-weight-bearing conditions

    NASA Technical Reports Server (NTRS)

    Jaspers, Stephen R.; Fagan, Julie M.; Satarug, Soisungwan; Cook, Paul H.; Tischler, Marc E.

    1988-01-01

    The effect of stretched and unstretched immobilization of a hind limb on the concentration and the metabolism of proteins in the hind-limb muscles of rats was investigated. The animals were divided into three groups: (1) weight-bearing controls, (2) tail-cast-suspended, and (3) suspended, with one hind limb immobilized with the ankle in dorsiflexion (30-40 deg angle) and the other freely moving. It was found that unloading the hind limbs for 6 days by tail cast suspension caused soleus to atrophy and reduced growth of the gastrocnemius and plantaris muscles; unloading resulted in a higher degradation rate and lower synthesis rate in both in vitro and in vivo. Chronic stretch of the unloaded soleus not only prevented its atrophy but led to significant hypertrophy, relative to weight-bearing controls, with increases in both the sarcoplasmic and myofibrillar protein fractions. Immobilizing one ankle in dorsiflexion prevented the inhibition of growth in the plantaris and gastrocnemius muscles due to unloading.

  11. Effect of spaceflight on the non-weight-bearing bones of rat skeleton.

    PubMed

    Simmons, D J; Russell, J E; Winter, F; Tran Van, P; Vignery, A; Baron, R; Rosenberg, G D; Walker, W V

    1983-03-01

    Male Wistar rats prelabeled with tetracycline to mark surfaces of bone and tooth formation-mineralization were placed into orbit for 18.5 days aboard the Soviet COSMOS-1129 Biosatellite. They were injected with tetracycline for a second and third time on the 6th and 27th days, respectively, after recovery of the Biosatellite. Spaceflight did not alter the rate of periosteal bone formation in the non-weight-bearing ribs and regions of the mandibles, which were covered by masticatory muscles. Bone formation-calcification rates were impaired at those sites in the jaw that had no contiguous muscle (molar region). The remodeling activity on the alveolar bone around the buccal roots of the molar teeth was significantly reduced but without creating a negative balance between formative and resorptive activities. Total Ca, P, and hydroxyproline concentrations in the jaws, incisors, and ribs were normal after spaceflight, but gravity density fractionation studies indicated that in the jaws alone, O-G conditions caused a delay in the maturation of bone mineral and matrix. A 29-day postflight recovery period at earth's gravity was sufficient to fully correct these anomalies. Relative to tooth formation, relatively normal circadian and infradian biorhythmic periodicities of Ca and P in dentin and enamel were maintained during spaceflight. We conclude that most of the non-weight-bearing bones of the rat skeleton are at risk to the effects of hypogravity. PMID:6829791

  12. [Weight-bearing early after osteosynthesis of the femoral neck by nail-plate (100 cases)].

    PubMed

    Langlais, F; Burdin, P; Bourgin, T; Sassi, N; Levasseur, M; Chagneau, F

    1987-01-01

    One hundred trochanteric or transcervical fractures, 64 of which were in patients more than 75 years old, were treated by internal fixation with a THS nail-plate. This device is characterised by a better bending strength than a one-piece nail-plate and a design which limits the risk of displacement of the screw in the head so that immediate weight-bearing can be allowed. Weight was borne on the limb in 81 cases at the tenth post-operative day. It did not improve the mortality, there being 17 deaths by the third month but it greatly helped post-operative care and rehabilitation without producing any additional complications. As a result, 43 per cent of patients could return home by the 45th post-operative day and 74 per cent had recovered their previous level of autonomy within three months of operation. There were only four mechanical complications, all in transcervical fractures: one crack fracture in the femoral head and three displacements following inadequate reduction, treated by prosthetic replacement. The follow-up of 80 patients at three months showed that consolidation always developed between the 45th and 90th day with full weight-bearing and a stable radiological picture. There was no intra-articular penetration or bending of the screw and no break-out of the implant. Whilst it is a definite advance in the treatment of trochanteric fractures, a longer follow-up is needed to determine its place compared with prostheses in transcervical fractures. PMID:3444942

  13. Kinematic and dynamic gait compensations in a rat model of lumbar radiculopathy and the effects of tumor necrosis factor-alpha antagonism

    PubMed Central

    2011-01-01

    Introduction Tumor necrosis factor-α (TNFα) has received significant attention as a mediator of lumbar radiculopathy, with interest in TNF antagonism to treat radiculopathy. Prior studies have demonstrated that TNF antagonists can attenuate heightened nociception resulting from lumbar radiculopathy in the preclinical model. Less is known about the potential impact of TNF antagonism on gait compensations, despite being of clinical relevance. In this study, we expand on previous descriptions of gait compensations resulting from lumbar radiculopathy in the rat and describe the ability of local TNF antagonism to prevent the development of gait compensations, altered weight bearing, and heightened nociception. Methods Eighteen male Sprague-Dawley rats were investigated for mechanical sensitivity, weight-bearing, and gait pre- and post-operatively. For surgery, tail nucleus pulposus (NP) tissue was collected and the right L5 dorsal root ganglion (DRG) was exposed (Day 0). In sham animals, NP tissue was discarded (n = 6); for experimental animals, autologous NP was placed on the DRG with or without 20 μg of soluble TNF receptor type II (sTNFRII, n = 6 per group). Spatiotemporal gait characteristics (open arena) and mechanical sensitivity (von Frey filaments) were assessed on post-operative Day 5; gait dynamics (force plate arena) and weight-bearing (incapacitance meter) were assessed on post-operative Day 6. Results High-speed gait characterization revealed animals with NP alone had a 5% decrease in stance time on their affected limbs on Day 5 (P ≤0.032). Ground reaction force analysis on Day 6 aligned with temporal changes observed on Day 5, with vertical impulse reduced in the affected limb of animals with NP alone (area under the vertical force-time curve, P <0.02). Concordant with gait, animals with NP alone also had some evidence of affected limb mechanical allodynia on Day 5 (P = 0.08) and reduced weight-bearing on the affected limb on Day 6 (P <0.05). Delivery of sTNFRII at the time of NP placement ameliorated signs of mechanical hypersensitivity, imbalanced weight distribution, and gait compensations (P <0.1). Conclusions Our data indicate gait characterization has value for describing early limb dysfunctions in pre-clinical models of lumbar radiculopathy. Furthermore, TNF antagonism prevented the development of gait compensations subsequent to lumbar radiculopathy in our model. PMID:21871102

  14. Soleus Fiber Force and Maximal Shortening Velocity After Non-Weight Bearing with Intermittent Activity

    NASA Technical Reports Server (NTRS)

    Widrick, Jeffrey J.; Bangart, Jill J.; Karhanek, Miloslav; Fitts, Robert H.

    1996-01-01

    This study examined the effectiveness of intermittent weight bearing (IWB) as a countermeasure to non-weight-bearing (NWB)-induced alterations in soleus type 1 fiber force (in mN), tension (P(sub o); force per fiber cross-sectional area in kN/sq m), and maximal unloaded shortening velocity (V(sub o), in fiber lengths/s). Adult rats were assigned to one of the following groups: normal weight bearing (WB), 14 days of hindlimb NWB (NWB group), and 14 days of hindlimb NWB with IWB treatments (IWB group). The IWB treatment consisted of four 10-min periods of standing WB each day. Single, chemically permeabilized soleus fiber segments were mounted between a force transducer and position motor and were studied at maximal Ca(2+) activation, after which type 1 fiber myosin heavy-chain composition was confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. NWB resulted in a loss in relative soleus mass (-45%), with type 1 fibers displaying reductions in diameter (-28%) and peak isometric force (-55%) and an increase in V(sub o) (+33%). In addition, NWB induced a 16% reduction in type 1 fiber P., a 41% reduction in type 1 fiber peak elastic modulus [E(sub o), defined as ((delta)force/(delta)length x (fiber length/fiber cross-sectional area] and a significant increase in the P(sub o)/E(sub o) ratio. In contrast to NWB, IWB reduced the loss of relative soleus mass (by 22%) and attenuated alterations in type 1 fiber diameter (by 36%), peak force (by 29%), and V(sub o)(by 48%) but had no significant effect on P(sub o), E(sub o) or P(sub o)/E(sub o). These results indicate that a modest restoration of WB activity during 14 days of NWB is sufficient to attenuate type 1 fiber atrophy and to partially restore type 1 peak isometric force and V(sub o) to WB levels. However, the NWB-induced reductions in P(sub o) and E(sub o) which we hypothesize to be due to a decline in the number and stiffness of cross bridges, respectively, are considerably less responsive to this countermeasure treatment.

  15. A novel tool for continuous fracture aftercare - Clinical feasibility and first results of a new telemetric gait analysis insole.

    PubMed

    Braun, Benedikt J; Bushuven, Eva; Hell, Rebecca; Veith, Nils T; Buschbaum, Jan; Holstein, Joerg H; Pohlemann, Tim

    2016-02-01

    Weight bearing after lower extremity fractures still remains a highly controversial issue. Even in ankle fractures, the most common lower extremity injury no standard aftercare protocol has been established. Average non weight bearing times range from 0 to 7 weeks, with standardised, radiological healing controls at fixed time intervals. Recent literature calls for patient-adapted aftercare protocols based on individual fracture and load scenarios. We show the clinical feasibility and first results of a new, insole embedded gait analysis tool for continuous monitoring of gait, load and activity. Ten patients were monitored with a new, independent gait analysis insole for up to 3 months postoperatively. Strict 20kg partial weight bearing was ordered for 6 weeks. Overall activity, load spectrum, ground reaction forces, clinical scoring and general health data were recorded and correlated. Statistical analysis with power analysis, t-test and Spearman correlation was performed. Only one patient completely adhered to the set weight bearing limit. Average time in minutes over the limit was 374min. Based on the parameters load, activity, gait time over 20kg weight bearing and maximum ground reaction force high and low performers were defined after 3 weeks. Significant difference in time to painless full weight bearing between high and low performers was shown. Correlation analysis revealed a significant correlation between weight bearing and clinical scoring as well as pain (American Orthopaedic Foot and Ankle Society (AOFAS) Score rs=0.74; Olerud-Molander Score rs=0.93; VAS pain rs=-0.95). Early, continuous gait analysis is able to define aftercare performers with significant differences in time to full painless weight bearing where clinical or radiographic controls could not. Patient compliance to standardised weight bearing limits and protocols is low. Highly individual rehabilitation patterns were seen in all patients. Aftercare protocols should be adjusted to real-time patient conditions, rather than fixed intervals and limits. With a real-time measuring device high performers could be identified and influenced towards optimal healing conditions early, while low performers are recognised and missing healing influences could be corrected according to patient condition. PMID:26626806

  16. Citrus unshiu peel extract alleviates cancer-induced weight loss in mice bearing CT-26 adenocarcinoma

    PubMed Central

    Kim, Aeyung; Im, Minju; Gu, Min Jung; Ma, Jin Yeul

    2016-01-01

    Skeletal muscle atrophy is a critical feature of cancer-induced cachexia, caused by pro-cachectic factors secreted by host cells and tumor cells. Therefore, blockade of these factors has considered a reasonable target for pharmacological and nutritional interventions to prevent skeletal muscle loss under cancer-induced cachexia. Citrus unshiu peel (CUP) has been used for treating the common cold, dyspepsia, and bronchial discomfort and reported to have pharmacological activities against inflammation, allergy, diabetes, and viral infection. In the present study, we observed that daily oral administration of water extract of CUP (WCUP) to male BALB/c mice bearing CT-26 adenocarcinoma remarkably reduced the losses in final body weight, carcass weight, gastrocnemius muscle, epididymal adipose tissue, and hemoglobin (Hb), compared with saline treatment. The levels of serum IL-6 and muscle-specific E3 ligases elevated by tumor burden were also considerably reduced by WCUP administration. In an in vitro experiment, WCUP efficiently suppressed the production of pro-cachectic cytokines in immune cells as well as cancer cells. In addition, WCUP treatment attenuated C2C12 skeletal muscle cell atrophy caused by cancer cells. These findings collectively suggest that WCUP is beneficial as a nutritional supplement for the management of cancer patients with severe weight loss. PMID:27064118

  17. Citrus unshiu peel extract alleviates cancer-induced weight loss in mice bearing CT-26 adenocarcinoma.

    PubMed

    Kim, Aeyung; Im, Minju; Gu, Min Jung; Ma, Jin Yeul

    2016-01-01

    Skeletal muscle atrophy is a critical feature of cancer-induced cachexia, caused by pro-cachectic factors secreted by host cells and tumor cells. Therefore, blockade of these factors has considered a reasonable target for pharmacological and nutritional interventions to prevent skeletal muscle loss under cancer-induced cachexia. Citrus unshiu peel (CUP) has been used for treating the common cold, dyspepsia, and bronchial discomfort and reported to have pharmacological activities against inflammation, allergy, diabetes, and viral infection. In the present study, we observed that daily oral administration of water extract of CUP (WCUP) to male BALB/c mice bearing CT-26 adenocarcinoma remarkably reduced the losses in final body weight, carcass weight, gastrocnemius muscle, epididymal adipose tissue, and hemoglobin (Hb), compared with saline treatment. The levels of serum IL-6 and muscle-specific E3 ligases elevated by tumor burden were also considerably reduced by WCUP administration. In an in vitro experiment, WCUP efficiently suppressed the production of pro-cachectic cytokines in immune cells as well as cancer cells. In addition, WCUP treatment attenuated C2C12 skeletal muscle cell atrophy caused by cancer cells. These findings collectively suggest that WCUP is beneficial as a nutritional supplement for the management of cancer patients with severe weight loss. PMID:27064118

  18. Reductions in knee joint forces with weight loss are attenuated by gait adaptations in class III obesity.

    PubMed

    DeVita, Paul; Rider, Patrick; Hortobágyi, Tibor

    2016-03-01

    A consensus exists that high knee joint forces are a precursor to knee osteoarthritis and weight loss reduces these forces. Because large weight loss also leads to increased step length and walking velocity, knee contact forces may be reduced less than predicted by the magnitude of weight loss. The purpose was to determine the effects of weight loss on knee muscle and joint loads during walking in Class III obese adults. We determined through motion capture, force platform measures and biomechanical modeling the effects of weight loss produced by gastric bypass surgery over one year on knee muscle and joint loads during walking at a standard, controlled velocity and at self-selected walking velocities. Weight loss equaling 412N or 34% of initial body weight reduced maximum knee compressive force by 824N or 67% of initial body weight when walking at the controlled velocity. These changes represent a 2:1 reduction in knee force relative to weight loss when walking velocity is constrained to the baseline value. However, behavioral adaptations including increased stride length and walking velocity in the self-selected velocity condition attenuated this effect by ∼50% leading to a 392N or 32% initial body weight reduction in compressive force in the knee joint. Thus, unconstrained walking elicited approximately 1:1 ratio of reduction in knee force relative to weight loss and is more indicative of walking behavior than the standard velocity condition. In conclusion, massive weight loss produces dramatic reductions in knee forces during walking but when patients stride out and walk faster, these favorable reductions become substantially attenuated. PMID:26979878

  19. Quantitative Alterations in the Function of Bone Forming Cells Due to Reduced Weight Bearing

    NASA Technical Reports Server (NTRS)

    Doty, S. B.

    1985-01-01

    Rats subjected to spaceflight or suspended in a non-weight bearing position for 2 to 3 weeks, show a significant reduction in new bone formation. This reduction is associated with a decrease in akaline phosphatase activity in the differentiated osteoblast population. Those cells in the siaphyseal region of bone are more affected than the same cell type in metaphyseal bone. Measurements of alkaline phosphate activity in specific regions of bone, and the autoradiographic localization of H(3) proline in bone forming areas are described. Concomitant with decreased bone matrix synthesis, the osteoblast population also demonstrate changes in the Golgi/lysosomal complex as a result of whole animal suspension. Morphometric techniques are being applied for quantitation of the lysosomal population and the percentage of lysosomal or Golgi bodies containing acid phosphatase activity.

  20. Effects of ground semen collection on weight bearing on hindquarters, libido, and semen parameters in stallions.

    PubMed

    Burger, D; Meroni, G; Thomas, S; Sieme, H

    2015-09-15

    Collection of semen on the ground from the standing stallion represents an alternative method to dummy mount semen collection and is of increasing popularity for sport stallions, males suffering from health problems, or in studs without a dummy or suitable mare at disposal. Our aim was to collect and compare spermatological and physiological data associated with traditional and ground semen collection. Twelve of 23 Franches-Montagnes stallions were selected to carry out semen collection on a dummy and while standing in a crossed experimental protocol. Semen quantity and quality parameters, weight bearing on hindquarters, and behavioral and libido data were recorded. Ground versus dummy mount semen collection was accompanied by lower seminal volume (15.9 14.6 vs. 22.0 13.3 mL; P < 0.01) and lower total sperm count (4.913 2.721 10(9) vs. 6.544 2.856 10(9) sperm; P < 0.001). No significant differences were found concerning sperm motility and viability. Time to ejaculation was longer, and the number of attempts to ejaculation was higher (P = 0.053) in the standing position compared with the mount on the dummy. A higher (P < 0.01) amount of tail flagging was manifested by the stallions during ejaculation on the dummy compared to when standing. There was no difference in weight bearing on hindquarters when comparing dummy collection (51.2 2.5%) and standing collection (48.9 5.5%). Ground semen collection can be considered as a viable option for stallions that cannot mount a dummy or a mare. However, it requires training and may be not easily accepted by all stallions. Owners should be advised that ground semen collection is associated with significantly lower sperm numbers than with dummy mount semen collection. PMID:26050613

  1. Reliability and minimal detectable change of the weight-bearing lunge test: A systematic review.

    PubMed

    Powden, Cameron J; Hoch, Johanna M; Hoch, Matthew C

    2015-08-01

    Ankle dorsiflexion range of motion (DROM) is often a point of emphasis during the rehabilitation of lower extremity pathologies. With the growing popularity of weight-bearing DROM assessments, several versions of the weight-bearing lunge (WBLT) test have been developed and numerous reliability studies have been conducted. The purpose of this systematic review was to critically appraise and synthesize the studies which examined the reliability and responsiveness of the WBLT to assess DROM. A systematic search of PubMed and EBSCO Host databases from inception to September 2014 was conducted to identify studies whose primary aim was assessing the reliability of the WBLT. The Quality Appraisal of Reliability Studies assessment tool was utilized to determine the quality of included studies. Relative reliability was examined through intraclass correlation coefficients (ICC) and responsiveness was evaluated through minimal detectable change (MDC). A total of 12 studies met the eligibility criteria and were included. Nine included studies assessed inter-clinician reliability and 12 included studies assessed intra-clinician reliability. There was strong evidence that inter-clinician reliability (ICC = 0.80-0.99) as well as intra-clinician reliability (ICC = 0.65-0.99) of the WBLT is good. Additionally, average MDC scores of 4.6° or 1.6 cm for inter-clinician and 4.7° or 1.9 cm for intra-clinician were found, indicating the minimal change in DROM needed to be outside the error of the WBLT. This systematic review determined that the WBLT, regardless of method, can be used clinically to assess DROM as it provides consistent results between one or more clinicians and demonstrates reasonable responsiveness. PMID:25704110

  2. Slow Recovery of Weight Bearing After Stabilization of Long-Bone Fractures Using Elastic Stable Intramedullary Nails in Children.

    PubMed

    Lardelli, Patrizia; Frech-Dörfler, Martina; Holland-Cunz, Stefan; Mayr, Johannes

    2016-03-01

    Stabilization of diaphyseal long-bone fractures using elastic stable intramedullary nails (ESIN) in children promises early mobilization and rapid resumption of full weight bearing.We evaluated the duration of postoperative functional rehabilitation after ESIN, measured by the time from stabilization until first partial weight bearing, full weight bearing, and resumption of school sports.Fifty children with unstable, displaced fractures of the femur or lower leg treated with ESIN between 2002 and 2012 were included in this retrospective analysis. We classified fractures according to the pediatric comprehensive classification of fractures (PCCF).Thirty-five children sustained a femur fracture, and 15 children had a fracture of the lower leg or tibia. The surgeons in charge applied an additional plaster cast in 7 of 15 children who suffered a lower leg fracture. The postoperative time interval until full weight bearing in the group of children who had suffered transverse or short oblique femur fractures was significantly shorter (median: 4.4 weeks; range: 0.1-9.1 weeks) than that in the group who had sustained more complex fracture patterns (median: 6.8 weeks; range: 2.9-13.9 weeks; P = 0.04). Similarly, transverse and short oblique lower leg and tibia fractures required less time until full weight bearing (median: 4.1 weeks; range 2.7-6.0 weeks) than complex lower leg fractures (median: 6.1 weeks; range: 1.3-12.9 weeks; P = 0.04).ESIN proved fairly effective in restoring full weight bearing in transverse or short oblique fractures of the lower extremities but was less effective in complex fractures. PMID:26986106

  3. Mesh skin graft and digital pad transfer to reconstruct the weight-bearing surface in a dog

    PubMed Central

    Rahal, Sheila C.; Mortari, Ana C.; Morishin Filho, Milton M.

    2007-01-01

    A 2-month-old dog was presented with injuries involving both hind paws. Only the 5th digit and its digital pad were present on the right paw. Following a full-thickness skin graft, the 5th digital pad was transferred distal to the metatarsal bones. The transferred pad permitted weight-bearing on the limb. PMID:18189047

  4. Venous emptying from the foot: influences of weight bearing, toe curls, electrical stimulation, passive compression, and posture.

    PubMed

    Broderick, Barry J; Corley, Gavin J; Quondamatteo, Fabio; Breen, Paul P; Serrador, Jorge; Ólaighin, Gearóid

    2010-10-01

    This study investigated the hemodynamic properties of the plantar venous plexus (PVP), a peripheral venous pump in the human foot, with Doppler ultrasound. We investigated how different ways of introducing mechanical changes vary in effectiveness of displacing blood volume from the PVP. The contribution of the PVP was analyzed during both natural and device-elicited compressions. Natural compressions consisted of weight bearing on the foot and toe curl exercises. Device-elicited compressions consisted of intermittent pneumatic compression (IPC) of the foot and electrically elicited foot muscle contractions. Ten healthy participants had their posterior tibial, peroneal, anterior tibial, and popliteal vein blood flow monitored while performing these natural and device-elicited compressions of the PVP supine and in an upright position. Results indicated that 1) natural compression of the PVP, weight bearing and toe curls, expelled a significantly larger volume of blood than device-elicited PVP compression, IPC and electrical stimulation; 2) there was no difference between the venous volume elicited by weight bearing and by toe curls; 3) expelled venous volume recorded at the popliteal vein under all test conditions was significantly greater than that recorded from the posterior tibial and peroneal veins; 4) there was no significant difference between the volume in the posterior tibial and peroneal veins; 5) ejected venous volume recorded in the upright position was significantly higher than that recorded in the supine position. Our study shows that weight bearing and toe curls make similar contributions to venous emptying of the foot. PMID:20705946

  5. Comparison of dermatoscopic images of acral lentiginous melanoma and acral melanocytic nevus occurring on body weight-bearing areas

    PubMed Central

    Watanabe, Soko; Sawada, Mizuki; Ishizaki, Sumiko; Kobayashi, Ken; Tanaka, Masaru

    2014-01-01

    Background: Because body weight-bearing produces a shift in the horny layer, acral melanocytic nevus on the body weight-bearing area of the sole showed a regular fibrillar pattern (FP) due to slanting of the melanin columns in the horny layer. On the other hand, acral lentiginous melanoma (ALM) on the body weight-bearing area of the sole tended to show irregular fibrillar pattern showing rather structureless pigmentation instead of a parallel ridge pattern, which is due to the shift of the horny layer. Objective: To elucidate the subtle difference between the regular FP of nevus and irregular FP in ALM. Methods: In this study, the dermatoscopic features of five cases of ALM and five cases of acral melanocytic nevus on the weight-bearing area of the sole were compared. Results: All the cases with nevi showed regular FP showing regular distribution of fibrils, whereas all the melanomas showed irregular distribution of fibrils and colors. Fibrils in nevi tended to be clear at the furrows and dim at the ridges. White fibrils corresponding to the eccrine ducts in the horny layer were more often present on the ridges in ALM, which showed negative FP. Conclusion: Differentiating between the regular and irregular FP, including negative FP, might be helpful for the discrimination of melanoma from nevus. PMID:25396085

  6. Benign acute childhood myositis--a rare cause of abnormal gait.

    PubMed

    Hall, Gregory; Schranz, Craig I

    2014-02-01

    Benign acute childhood myositis is a rare postviral myositis seen in school-aged children after a common upper respiratory infection (URI), most commonly caused by influenza [J Microbiol Immunol Infect 2004;37:95-98]. Predominantly seen in boys, this condition causes bilateral calf tenderness and pain with ambulation, often presenting as a refusal to bear weight. To avoid activation within the gastroc-soleus complex, the child will frequently compensate with a “Frankenstein gait,” described as a stiff-legged posture with shuffling gait [CMAJ 2009;181:711-713]. The child may also walk on his toes or refuse to walk at all. This refusal to bear weight can be alarming to both providers and parents, resulting in extensive workups. We present the case of a 5-year-old boy who presented to the emergency department with a chief complaint of leg pain and refusal to walk. Further history revealed a resolved URI approximately 5 days prior. He was noted to have an elevated creatinine kinase with no evidence of renal insufficiency. He had no progression or complications, and his symptoms resolved spontaneously with minimal supportive treatment. Benign acute childhood myositis should be considered within the broad differential that surrounds a limping child or one who refuses to bear weight. Having insight into the condition with its characteristic gait abnormalities and associated URI history can often prevent extensive workups and be treated supportively in the outpatient setting. PMID:24126025

  7. Coordination strategies for limb forces during weight-bearing locomotion in normal rats, and in rats spinalized as neonates

    PubMed Central

    Giszter, Simon F; Davies, Michelle R; Graziani, Virginia

    2010-01-01

    Some rats spinally transected as neonates (ST rats) achieve weight-supporting independent locomotion. The mechanisms of coordinated hindlimb weight support in such rats are not well understood. To examine these in such ST rats and normal rats, rats with better than 60% of weight supported steps on a treadmill as adults were trained to cross an instrumented runway. Ground reaction forces, coordination of hindlimb and forelimb forces and the motions of the center of pressure were assessed. Normal rats crossed the runway with a diagonal trot. On average hindlimbs bore about 80% of the vertical load carried by forelimbs, although this varied. Forelimbs and hindlimb acted synergistically to generate decelerative and propulsive rostrocaudal forces, which averaged 15% of body weight with maximums of 50% . Lateral forces were very small (<8% of body weight). Center of pressure progressed in jumps along a straight line with mean lateral deviations <1 cm. ST rats hindlimbs bore about 60% of the vertical load of forelimbs, significantly less compared to intact (p<0.05). ST rats showed similar mean rostrocaudal forces, but with significantly larger maximum fluctuations of up to 80% of body weight (p<0.05). Joint force-plate recordings showed forelimbs and hindlimb rostrocaudal forces in ST rats were opposing and significantly different from intact rats (p<0.05). Lateral forces were ~20% of body weight and significantly larger than in normal rats (p<0.05). Center of pressure zig-zagged, with mean lateral deviations of ~ 2cm and a significantly larger range (p<0.05). The haunches were also observed to roll more than normal rats. The locomotor strategy of injured rats using limbs in opposition was presumably less efficient but their complex gait was statically stable. Because forelimbs and hindlimbs acted in opposition, the trunk was held compressed. Force coordination was likely managed largely by the voluntary control in forelimbs and trunk. PMID:18612631

  8. Acoustic Gaits: Gait Analysis With Footstep Sounds.

    PubMed

    Altaf, M Umair Bin; Butko, Taras; Juang, Biing-Hwang Fred

    2015-08-01

    We describe the acoustic gaits-the natural human gait quantitative characteristics derived from the sound of footsteps as the person walks normally. We introduce the acoustic gait profile, which is obtained from temporal signal analysis of sound of footsteps collected by microphones and illustrate some of the spatio-temporal gait parameters that can be extracted from the acoustic gait profile by using three temporal signal analysis methods-the squared energy estimate, Hilbert transform and Teager-Kaiser energy operator. Based on the statistical analysis of the parameter estimates, we show that the spatio-temporal parameters and gait characteristics obtained using the acoustic gait profile can consistently and reliably estimate a subset of clinical and biometric gait parameters currently in use for standardized gait assessments. We conclude that the Teager-Kaiser energy operator provides the most consistent gait parameter estimates showing the least variation across different sessions and zones. Acoustic gaits use an inexpensive set of microphones with a computing device as an accurate and unintrusive gait analysis system. This is in contrast to the expensive and intrusive systems currently used in laboratory gait analysis such as the force plates, pressure mats and wearable sensors, some of which may change the gait parameters that are being measured. PMID:25769144

  9. Use of weight-bearing MRI for evaluating wheelchair cushions based on internal soft-tissue deformations under ischial tuberosities.

    PubMed

    Shabshin, Nogah; Zoizner, Gil; Herman, Amir; Ougortsin, Vlad; Gefen, Amit

    2010-01-01

    Deep tissue injury (DTI) is a severe type of pressure ulcer, in which damage initiates under intact skin, in soft tissues that are mechanically deformed by load-bearing bony prominences. Sitting-acquired DTI typically occurs in the gluteus muscles that could sustain deformations by the weight-bearing ischial tuberosities (ITs). No clinical method currently exists for measuring internal tissue deformations; so design and selection of wheelchair cushions are based mostly on measuring sitting pressures. Our objective was to evaluate the influence of different commercial cushions on internal soft-tissue deformations under the ITs, using weight-bearing magnetic resonance imaging (MRI). We specifically compared muscle, superficial fat, and effective (muscle and fat together) tissue deformations while subjects (n = 10) sat on four cushions (two viscoelastic and two foam) and directly on a rigid support. Deformations were maximal in muscle tissue (mean approximately 70%), twice more the amount than in fat (approximately 30%). Effective soft-tissue deformations were approximately 50% to approximately 60%. Although cushions mildly reduced muscle deformations in the order of 10%, theoretically, our interpretation suggests that this deformation level adds safe sitting time. This study demonstrated that weight-bearing MRI is applicable for evaluating wheelchair cushions and, in the future, may be a tool to systematically support cushion design and selection. PMID:20437325

  10. Positional pelvic organ prolapse (POP) evaluation using open, weight-bearing magnetic resonance imaging (MRI)

    PubMed Central

    Friedman, Boris; Stothers, Lynn; Lazare, Darren; Macnab, Andrew

    2015-01-01

    Introduction: Magnetic resonance imaging (MRI) of patients with pelvic organ prolapse (POP) is completed in the supine position. Open magnetic resonance imaging (MRO) uses vertical magnets, allowing imaging in a variety of upright postures. This pilot study used MRO to evaluate the change of prolapse in different positions compared to non-prolapsed images. Methods: In total, 11 women (6 POP, 5 controls) aged 24 to 65 years had 12 MRO images (midline sagittal pelvic line) consecutively when supine, sitting and standing with a full and empty bladder. Lengths between the lowest point of the bladder to the pubococcygeal (PC) and pubopromontoreal (PP) lines in each image were compared, and the ratio of bladder area under the PC and PP lines to the total bladder area. Results: Significant elongation between the PC line and lowest point of the bladder was evident in subjects with POP comparing supine and standing images (p = 0.03), but not controls (p = 0.07). Similarly, this axis was significantly longer in cystocele subjects versus controls only in the standing position. Bladder area under the PC line was significantly increased between supine and standing positions only among subjects with cystocele (p < 0.01), and significantly larger among the study group in the standing position (p < 0.005), less significant in the supine position (p = 0.015), and not significant in the sitting position (p = 0.3). Conclusions: MRO imaging allows us to investigate the effects of upright position and weight bearing on the staging of POP. Imaging patients when sitting and standing identified that significant changes occur in the maximal descent of the bladder. PMID:26225170

  11. Kinematic and dynamic gait compensations resulting from knee instability in a rat model of osteoarthritis

    PubMed Central

    2012-01-01

    Introduction Osteoarthritis (OA) results in pain and disability; however, preclinical OA models often focus on joint-level changes. Gait analysis is one method used to evaluate both preclinical OA models and OA patients. The objective of this study is to describe spatiotemporal and ground reaction force changes in a rat medial meniscus transection (MMT) model of knee OA and to compare these gait measures with assays of weight bearing and tactile allodynia. Methods Sixteen rats were used in the study. The medial collateral ligament (MCL) was transected in twelve Lewis rats (male, 200 to 250 g); in six rats, the medial meniscus was transected, and the remaining six rats served as sham controls. The remaining four rats served as naïve controls. Gait, weight-bearing as measured by an incapacitance meter, and tactile allodynia were assessed on postoperative days 9 to 24. On day 28, knee joints were collected for histology. Cytokine concentrations in the serum were assessed with a 10-plex cytokine panel. Results Weight bearing was not affected by sham or MMT surgery; however, the MMT group had decreased mechanical paw-withdrawal thresholds in the operated limb relative to the contralateral limb (P = 0.017). The gait of the MMT group became increasingly asymmetric from postoperative days 9 to 24 (P = 0.020); moreover, MMT animals tended to spend more time on their contralateral limb than their operated limb while walking (P < 0.1). Ground reaction forces confirmed temporal shifts in symmetry and stance time, as the MMT group had lower vertical and propulsive ground reaction forces in their operated limb relative to the contralateral limb, naïve, and sham controls (P < 0.05). Levels of interleukin 6 in the MMT group tended to be higher than naïve controls (P = 0.072). Histology confirmed increased cartilage damage in the MMT group, consistent with OA initiation. Post hoc analysis revealed that gait symmetry, stance time imbalance, peak propulsive force, and serum interleukin 6 concentrations had significant correlations to the severity of cartilage lesion formation. Conclusion These data indicate significant gait compensations were present in the MMT group relative to medial collateral ligament (MCL) injury (sham) alone and naïve controls. Moreover, these data suggest that gait compensations are likely driven by meniscal instability and/or cartilage damage, and not by MCL injury alone. PMID:22510443

  12. Synergistic ablation does not affect atrophy or altered myosin heavy chain expression in the non-weight bearing soleus muscle

    NASA Technical Reports Server (NTRS)

    Linderman, J. K.; Talmadge, R. J.; Gosselink, K. L.; Tri, P. N.; Roy, R. R.; Grindeland, R. E.

    1996-01-01

    The purpose of this study was to investigate whether the soleus muscle undergoes atrophy and alterations in myosin heavy chain (MHC) composition during non-weight bearing in the absence of synergists. Thirty-two female rats were randomly assigned to four groups: control (C), synergistic ablation (ABL) of the gastrocnemius and plantaris muscles to overload the soleus muscle, hindlimb suspension (HLS), or a combination of synergistic ablation and hindlimb suspension (HLS-ABL). After 28 days of hindlimb suspension, soleus atrophy was more pronounced in HLS (58%) than in HLS-ABL (43%) rats. Compared to C rats, non-weight bearing decreased mixed and myofibrillar protein contents and Type I MHC 49%, 45%, and 7%, respectively, in HLS animals. In addition, de novo expression of fast Type IIx and Type IIb MHC (5% and 2%, respectively) was observed in HLS animals. Similarly, when compared to C rats, mixed and myofibrillar protein contents and Type I MHC decreased 43%, 46%, and 4%, respectively, in HLS-ABL animals. Also, de novo expression of Type IIx (4%) and IIb (1%) MHC was observed. Collectively, these data indicate that the loss of muscle protein and Type I MHC, and the de novo expression of Type IIx and Type IIb MHC in the rat soleus occur independently of the presence of synergists during non-weight bearing. Furthermore, these results confirm the contention that soleus mass and MHC expression are highly sensitive to alterations in mechanical load.

  13. Biofeedback rehabilitation of posture and weight-bearing distribution in stroke: a center of foot pressure analysis

    PubMed Central

    De Nunzio, Alessandro Marco; Zucchella, Chiara; Spicciato, Francesca; Tortola, Paolo; Vecchione, Carmine; Pierelli, Francesco; Bartolo, Michelangelo

    2014-01-01

    Summary Weight bearing on the paretic lower extremity and transfer of weight from one lower extremity to the other are important goals of stroke rehabilitation. Improvements in these limb loading and weight transfer abilities have been shown to relate to improved performance of many functional activities. Unfortunately, valid and practical clinical measures of paretic lower extremity loading and weight transfer have not been identified. The purpose of this study was to quantitatively assess, through center of foot pressure (CoP) analysis of quiet upright stance control, recovery of paretic limb loading as a measure of weight transfer in early stroke subjects, testing the effectiveness of a targeted rehabilitation intervention based on audio-visual biofeedback. Thirty-seven adults with lower extremity motor impairment following unilateral, non-cerebellar stroke, were tested twice, at an interval of at least one month post stroke and following rehabilitation intervention aimed at correcting their asymmetrical weight bearing. The intervention was performed with (Study Group, SG) or without (Control Group, CG) a postural audio-visual biofeedback approach. Indices of postural stability and of balance control asymmetry were estimated by acquiring the movements of the CoP during quiet upright stance condition with or without visual input (eyes open, EO and eyes closed, EC). Clinical scales were also administered. Both the CG and the SG subjects showed improved control in upright stance posture as documented by significant improvements in the scale scores and indices of stability during both the EO and the EC condition. Only the SG showed a significantly reduced CoP index of asymmetry. The CoP index of asymmetry, correlating with clinical motor scales, is a valid measure of paretic limb loading during stroke recovery. Postural audio-visual biofeedback represented the more effective approach for reducing weight loading asymmetry of the lower limbs in stroke. PMID:25306123

  14. Effect of Different Bearing Ratios on the Friction between Ultrahigh Molecular Weight Polyethylene Ski Bases and Snow.

    PubMed

    Rohm, Sebastian; Knoflach, Christoph; Nachbauer, Werner; Hasler, Michael; Kaserer, Lukas; van Putten, Joost; Unterberger, Seraphin H; Lackner, Roman

    2016-05-18

    The purpose of this study was to analyze the effect of surfaces with different bearing ratios, but similar roughness heights, on the friction between ultrahigh molecular weight polyethylene (UHMWPE) and snow. On a linear tribometer positioned inside a cold chamber, the different samples were tested over a wide range of velocities and snow temperatures. The surface roughness was measured with a focus variation microscope and analyzed using the bearing ratio curve and its parameters. The surface energy was investigated by measuring the contact angles of a polar (water) and nonpolar (diiodmethane) liquid. The friction tests showed that the bearing ratio had a major effect on the friction between UHMWPE and snow. For temperatures close to the melting point a surface with wide grooves and narrow plateaus (nonbearing surface) performed well. For cold conditions, the friction was less for a surface with narrow grooves and wide plateaus (bearing surface). Interpretations of the results are given on the basis of mixed friction, with lubricated friction being dominant at higher snow temperatures and solid-solid interaction at lower ones. PMID:27115349

  15. Human Muscle Protein Synthetic Responses during Weight-Bearing and Non-Weight-Bearing Exercise: A Comparative Study of Exercise Modes and Recovery Nutrition

    PubMed Central

    Pasiakos, Stefan M.; McClung, Holly L.; Margolis, Lee M.; Murphy, Nancy E.; Lin, Gregory G.; Hydren, Jay R.; Young, Andrew J.

    2015-01-01

    Effects of conventional endurance (CE) exercise and essential amino acid (EAA) supplementation on protein turnover are well described. Protein turnover responses to weighted endurance exercise (i.e., load carriage, LC) and EAA may differ from CE, because the mechanical forces and contractile properties of LC and CE likely differ. This study examined muscle protein synthesis (MPS) and whole-body protein turnover in response to LC and CE, with and without EAA supplementation, using stable isotope amino acid tracer infusions. Forty adults (mean ± SD, 22 ± 4 y, 80 ± 10 kg, VO2peak 4.0 ± 0.5 L∙min-1) were randomly assigned to perform 90 min, absolute intensity-matched (2.2 ± 0.1 VO2 L∙m-1) LC (performed on a treadmill wearing a vest equal to 30% of individual body mass, mean ± SD load carried 24 ± 3 kg) or CE (cycle ergometry performed at the same absolute VO2 as LC) exercise, during which EAA (10 g EAA, 3.6 g leucine) or control (CON, non-nutritive) drinks were consumed. Mixed-muscle and myofibrillar MPS were higher during exercise for LC than CE (mode main effect, P < 0.05), independent of dietary treatment. EAA enhanced mixed-muscle and sarcoplasmic MPS during exercise, regardless of mode (drink main effect, P < 0.05). Mixed-muscle and sarcoplasmic MPS were higher in recovery for LC than CE (mode main effect, P < 0.05). No other differences or interactions (mode x drink) were observed. However, EAA attenuated whole-body protein breakdown, increased amino acid oxidation, and enhanced net protein balance in recovery compared to CON, regardless of exercise mode (P < 0.05). These data show that, although whole-body protein turnover responses to absolute VO2-matched LC and CE are the same, LC elicited a greater muscle protein synthetic response than CE. PMID:26474292

  16. Bone loss during partial weight bearing (1/6th gravity) is mitigated by resistance and aerobic exercise in mice

    NASA Astrophysics Data System (ADS)

    Boudreaux, R. D.; Metzger, C. E.; Macias, B. R.; Shirazi-Fard, Y.; Hogan, H. A.; Bloomfield, S. A.

    2014-06-01

    Astronauts on long duration missions continue to experience bone loss, as much as 1-2% each month, for up to 4.5 years after a mission. Mechanical loading of bone with exercise has been shown to increase bone formation, mass, and geometry. The aim of this study was to compare the efficacy of two exercise protocols during a period of reduced gravitational loading (1/6th body weight) in mice. Since muscle contractions via resistance exercise impart the largest physiological loads on the skeleton, we hypothesized that resistance training (via vertical tower climbing) would better protect against the deleterious musculoskeletal effects of reduced gravitational weight bearing when compared to endurance exercise (treadmill running). Young adult female BALB/cBYJ mice were randomly assigned to three groups: 1/6 g (G/6; n=6), 1/6 g with treadmill running (G/6+RUN; n=8), or 1/6 g with vertical tower climbing (G/6+CLB; n=9). Exercise was performed five times per week. Reduced weight bearing for 21 days was achieved through a novel harness suspension system. Treadmill velocity (12-20 m/min) and daily run time duration (32-51 min) increased incrementally throughout the study. Bone geometry and volumetric bone mineral density (vBMD) at proximal metaphysis and mid-diaphysis tibia were assessed by in vivo peripheral quantitative computed tomography (pQCT) on days 0 and 21 and standard dynamic histomorphometry was performed on undemineralized sections of the mid-diaphysis after tissue harvest. G/6 caused a significant decrease (P<0.001) in proximal tibia metaphysis total vBMD (-9.6%). These reductions of tibia metaphyseal vBMD in G/6 mice were mitigated in both G/6+RUN and G/6+CLB groups (P<0.05). After 21 days of G/6, we saw an absolute increase in tibia mid-diaphysis vBMD and in distal metaphysis femur vBMD in both G/6+RUN and G/6+CLB mice (P<0.05). Substantial increases in endocortical and periosteal mineralizing surface (MS/BS) at mid-diaphysis tibia in G/6+CLB demonstrate that bone formation can be increased even in the presence of reduced weight bearing. These data suggest that moderately vigorous endurance exercise and resistance training, through treadmill running or climb training mitigates decrements in vBMD during 21 days of reduced weight bearing. Consistent with our hypothesis, tower climb training, most pronounced in the tibia mid-diaphysis, provides a more potent osteogenic response compared to treadmill running.

  17. Study of the Polycarbonate-Urethane/Metal Contact in Different Positions during Gait Cycle

    PubMed Central

    Herrera, Antonio; Mateo, Jesús; Lobo-Escolar, Antonio

    2014-01-01

    Nowadays, a growing number of young and more active patients receive hip replacement. More strenuous activities in such patients involve higher friction and wear rates, with friction on the bearing surface being crucial to ensure arthroplasty survival in the long term. Over the last years, the polycarbonate-urethane has offered a feasible alternative to conventional bearings. A finite element model of a healthy hip joint was developed and adjusted to three gait phases (heel strike, mid-stance, and toe-off), serving as a benchmark for the assessment of the results of joint replacement model. Three equivalent models were made with the polycarbonate-urethane Tribofit system implanted, one for each of the three gait phases, after reproducing a virtual surgery over the respective healthy models. Standard body-weight loads were considered: 230% body-weight toe-off, 275% body-weight mid-stance, and 350% body-weight heel strike. Contact pressures were obtained for the different models. When comparing the results corresponding to the healthy model to polycarbonate-urethane joint, contact areas are similar and so contact pressures are within a narrower value range. In conclusion, polycarbonate-urethane characteristics are similar to those of the joint cartilage. So, it is a favorable alternative to traditional bearing surfaces in total hip arthroplasty, especially in young patients. PMID:25247180

  18. Weight-Bearing and Mobilization in the Postoperative Care of Ankle Fractures: A Systematic Review and Meta-Analysis of Randomized Controlled Trials and Cohort Studies

    PubMed Central

    Smeeing, Diederik P. J.; Houwert, Roderick M.; Briet, Jan Paul; Kelder, Johannes C.; Segers, Michiel J. M.; Verleisdonk, Egbert Jan M. M.; Leenen, Luke P. H.; Hietbrink, Falco

    2015-01-01

    Purpose To determine the effectiveness and safety of interventions used for rehabilitation after open reduction and internal fixation of ankle fractures. Methods A systematic review and meta-analysis was performed using both randomized trials and cohort studies. The effect of mobilization, weight-bearing, and unprotected weight-bearing as tolerated on postoperative recovery was compared using the Olerud Molander score, return to work/daily activities, and the rate of complications. Results A total of 25 articles were included. Ankle exercises resulted in earlier return to work and/or daily activities compared to immobilization (mean difference (MD) -20.76 days; 95% confidence interval (CI) -40.02 to -1.50). There was no difference in the rate of complications between exercises and immobilization (risk ratio (RR) 1.22; 95% CI 0.60 to 2.45) or between early and late weight-bearing (RR 1.26; 95%CI 0.56 to 2.85). Interpretation Results of this meta-analysis show that following ankle surgery, 1) active exercises accelerate return to work and daily activities compared to immobilization, 2) early weight-bearing tends to accelerate return to work and daily activities compared to late weight-bearing. Active exercises in combination with immediate weight-bearing may be a safe option. PMID:25695796

  19. Weight-Bearing Asymmetry in Relation to Measures of Impairment and Functional Mobility for People With Knee Osteoarthritis

    PubMed Central

    Christiansen, Cory L.; Stevens-Lapsley, Jennifer E.

    2010-01-01

    Objective To compare weight-bearing asymmetry (WBA) for people with unilateral knee osteoarthritis (OA) to healthy adults of similar age. In addition, associations between WBA and clinical measures of knee impairment and functional mobility were evaluated. Design Cross-sectional design with age-matched control (CTL) group. Setting Clinical research laboratory. Participants People with end-stage unilateral knee OA (n=50) (OA group) and healthy people (n=17) (CTL group) were enrolled in the study. Interventions Not applicable. Main Outcome Measures WBA during a Five Times Sit-to-Stand Test (FTSST) based on average vertical ground reaction force under each foot, self-reported knee pain assessed using a Numerical Pain Rating Scale, knee extensor strength asymmetry based on peak isometric knee extension torque, knee motion asymmetry based on maximum passive knee extension and flexion angles, FTSST time, Six-Minute Walk Test distance, and Stair Climbing Test time. Results The OA group demonstrated greater WBA than that of the CTL group during transitions between sitting and standing as measured by an absolute symmetry index (P = 0.015). No correlation was found between WBA and knee motion asymmetry, but comparisons of WBA to all the other outcome variables indicated fair relationships (ranging from r = 0.29 - 0.44). Conclusions Weight-bearing asymmetry during transitions between sitting and standing can serve as a clinically relevant measure related to both knee impairment and functional mobility for people with unilateral knee OA. PMID:20875509

  20. The Combination of the Tunnel View and Weight-Bearing Anteroposterior Radiographs Improves the Detection of Knee Arthritis

    PubMed Central

    Babatunde, Oladapo M.; Danoff, Jonathan R.; Patrick, David A.; Lee, Jonathan H.; Kazam, Jonathan K.; Macaulay, William

    2016-01-01

    Imaging used for the evaluation of knee pain has historically included weight-bearing anteroposterior (AP), lateral, and sunrise radiographs. We wished to evaluate the utility of adding the weight-bearing (WB) posteroanterior (PA) view of the knee in flexion. We hypothesize that (1) the WB tunnel view can detect radiographic osteoarthritis (OA) not visualized on the WB AP, (2) the combination of the AP and tunnel view increases the radiographic detection of OA, and (3) this may provide additional information to the clinician evaluating knee pain. We retrospectively reviewed the WB AP and tunnel view radiographs of 100 knees (74 patients) presenting with knee pain and analyzed for evidence of arthritis. The combination of the WB tunnel view and WB AP significantly increased the detection of joint space narrowing in the lateral (p < 0.001) and medial (p = 0.006) compartments over the AP view alone. The combined views significantly improved the identification of medial subchondral cysts (p = 0.022), sclerosis of the lateral tibial plateau (p = 0.041), and moderate-to-large osteophytes in the medial compartment (p = 0.012), intercondylar notch (p < 0.001), and tibial spine (p < 0.001). The WB tunnel view is an effective tool to provide additional information on affected compartments in the painful knee, not provided by the AP image alone. PMID:26925264

  1. Effect of spaceflight on the non-weight-bearing bones of rat skeleton

    NASA Technical Reports Server (NTRS)

    Simmons, D. J.; Russell, J. E.; Winter, F.; Tran Van, P.; Vignery, A.; Baron, R.; Rosenberg, G. D.; Walker, W. V.

    1983-01-01

    The effects of weightlessness on the integrated growth and remodeling of nonweight-bearing bones (the mandibles, teeth, and ribs) were studied. Rats prelabeled with tetracycline to mark the surfaces of bone and tooth formation were subjected to spaceflight conditions for 18.5 days, followed by further injections of tetracycline on days 6 and 29 postflight.Results show that spaceflight conditions did not alter the rate of periosteal bone formation in the ribs and regions of the mandibles covered by masticatory muscles, although bone formation-calcification rates were found to be impaired at those sites in the jaw that had no contiguous muscle (molar region). The remodeling activity on the alveolar bone around the buccal roots of the molar teeth was found to be significantly reduced. While total Ca, P, and hydroxyproline concentrations in the jaws, incisors, and ribs were normal after spaceflight, it was determined that weightless conditions caused a delay in the maturation of bone mineral and matrix in the jaws. These anomalies were found to be corrected by 29 days postflight. These results indicate that most of the nonweight-bearing bones of the rat skeleton are at risk to the effects of weightlessness.

  2. Gait Characteristic Analysis and Identification Based on the iPhone's Accelerometer and Gyrometer

    PubMed Central

    Sun, Bing; Wang, Yang; Banda, Jacob

    2014-01-01

    Gait identification is a valuable approach to identify humans at a distance. In this paper, gait characteristics are analyzed based on an iPhone's accelerometer and gyrometer, and a new approach is proposed for gait identification. Specifically, gait datasets are collected by the triaxial accelerometer and gyrometer embedded in an iPhone. Then, the datasets are processed to extract gait characteristic parameters which include gait frequency, symmetry coefficient, dynamic range and similarity coefficient of characteristic curves. Finally, a weighted voting scheme dependent upon the gait characteristic parameters is proposed for gait identification. Four experiments are implemented to validate the proposed scheme. The attitude and acceleration solutions are verified by simulation. Then the gait characteristics are analyzed by comparing two sets of actual data, and the performance of the weighted voting identification scheme is verified by 40 datasets of 10 subjects. PMID:25222034

  3. Gait pattern differences in children with unilateral cerebral palsy.

    PubMed

    Szopa, Andrzej; Domagalska-Szopa, Małgorzata; Czamara, Andrzej

    2014-10-01

    Children with cerebral palsy (CP) often have atypical body posture patterns and abnormal gait patterns resulting from functional strategies to compensate for primary anomalies that are directly attributable to damage to the central nervous system. Our previous study revealed two different postural patterns in children with unilateral CP: (1) a pattern with overloading of the affected body side and (2) a pattern with under-loading of the affected side. The purpose of present study was to test whether different gait patterns dependent on weight distribution between the affected and unaffected body sides could be detected in these children. The study included 45 outpatients with unilateral CP and 51 children with mild scoliosis (reference group). The examination consisted of two inter-related parts: paedobarographic measurements of the body mass distribution between the body sides and three-dimensional instrumented gait analysis. Using cluster analysis based on the Gillette Gait Index (GGI) values, three gait patterns were described: a scoliotic gait pattern and two hemiplegic gait patterns, corresponding to overloading/under-loading of the hemi-side, which are the pro-gravitational gait pattern (PGP) and the anti-gravitational gait pattern (AGP), respectively. The results of this study showed that subjects with AGP presented a higher degree of deviation from the normal gait than children with PGP. This proof that there are differences in the GGI between the AGP and PGP could be a starting point to identify kinematic differences between these gaits in a follow-up study. PMID:24946266

  4. Two Patients with Osteochondral Injury of the Weight-Bearing Portion of the Lateral Femoral Condyle Associated with Lateral Dislocation of the Patella

    PubMed Central

    Inoue, Hiroaki; Atsumi, Satoru; Ichimaru, Shohei; Fujiwara, Hiroyoshi; Kubo, Toshikazu

    2014-01-01

    Complications of patellar dislocation include osteochondral injury of the lateral femoral condyle and patella. Most cases of osteochondral injury occur in the anterior region, which is the non-weight-bearing portion of the lateral femoral condyle. We describe two patients with osteochondral injury of the weight-bearing surface of the lateral femoral condyle associated with lateral dislocation of the patella. The patients were 18- and 11-year-old females. Osteochondral injury occurred on the weight-bearing surface distal to the lateral femoral condyle. The presence of a free osteochondral fragment and osteochondral injury of the lateral femoral condyle was confirmed on MRI and reconstruction CT scan. Treatment consisted of osteochondral fragment fixation or microfracture, as well as patellar stabilization. Osteochondral injury was present in the weight-bearing portion of the lateral femoral condyle in both patients, suggesting that the injury was caused by friction between the patella and lateral femoral condyle when the patella was dislocated or reduced at about 90 flexion of the knee joint. These findings indicate that patellar dislocation may occur and osteochondral injury may extend to the weight-bearing portion of the femur even in deep flexion, when the patella is stabilized on the bones of the femoral groove. PMID:25506015

  5. Gait-related brain activity in people with Parkinson disease with freezing of gait.

    PubMed

    Peterson, Daniel S; Pickett, Kristen A; Duncan, Ryan; Perlmutter, Joel; Earhart, Gammon M

    2014-01-01

    Approximately 50% of people with Parkinson disease experience freezing of gait, described as a transient inability to produce effective stepping. Complex gait tasks such as turning typically elicit freezing more commonly than simple gait tasks, such as forward walking. Despite the frequency of this debilitating and dangerous symptom, the brain mechanisms underlying freezing remain unclear. Gait imagery during functional magnetic resonance imaging permits investigation of brain activity associated with locomotion. We used this approach to better understand neural function during gait-like tasks in people with Parkinson disease who experience freezing--"FoG+" and people who do not experience freezing--"FoG-". Nine FoG+ and nine FoG- imagined complex gait tasks (turning, backward walking), simple gait tasks (forward walking), and quiet standing during measurements of blood oxygen level dependent (BOLD) signal. Changes in BOLD signal (i.e. beta weights) during imagined walking and imagined standing were analyzed across FoG+ and FoG- groups in locomotor brain regions including supplementary motor area, globus pallidus, putamen, mesencephalic locomotor region, and cerebellar locomotor region. Beta weights in locomotor regions did not differ for complex tasks compared to simple tasks in either group. Across imagined gait tasks, FoG+ demonstrated significantly lower beta weights in the right globus pallidus with respect to FoG-. FoG+ also showed trends toward lower beta weights in other right-hemisphere locomotor regions (supplementary motor area, mesencephalic locomotor region). Finally, during imagined stand, FoG+ exhibited lower beta weights in the cerebellar locomotor region with respect to FoG-. These data support previous results suggesting FoG+ exhibit dysfunction in a number of cortical and subcortical regions, possibly with asymmetric dysfunction towards the right hemisphere. PMID:24595265

  6. Gait-Related Brain Activity in People with Parkinson Disease with Freezing of Gait

    PubMed Central

    Peterson, Daniel S.; Pickett, Kristen A.; Duncan, Ryan; Perlmutter, Joel; Earhart, Gammon M.

    2014-01-01

    Approximately 50% of people with Parkinson disease experience freezing of gait, described as a transient inability to produce effective stepping. Complex gait tasks such as turning typically elicit freezing more commonly than simple gait tasks, such as forward walking. Despite the frequency of this debilitating and dangerous symptom, the brain mechanisms underlying freezing remain unclear. Gait imagery during functional magnetic resonance imaging permits investigation of brain activity associated with locomotion. We used this approach to better understand neural function during gait-like tasks in people with Parkinson disease who experience freezing- “FoG+” and people who do not experience freezing- ”FoG−“. Nine FoG+ and nine FoG− imagined complex gait tasks (turning, backward walking), simple gait tasks (forward walking), and quiet standing during measurements of blood oxygen level dependent (BOLD) signal. Changes in BOLD signal (i.e. beta weights) during imagined walking and imagined standing were analyzed across FoG+ and FoG− groups in locomotor brain regions including supplementary motor area, globus pallidus, putamen, mesencephalic locomotor region, and cerebellar locomotor region. Beta weights in locomotor regions did not differ for complex tasks compared to simple tasks in either group. Across imagined gait tasks, FoG+ demonstrated significantly lower beta weights in the right globus pallidus with respect to FoG−. FoG+ also showed trends toward lower beta weights in other right-hemisphere locomotor regions (supplementary motor area, mesencephalic locomotor region). Finally, during imagined stand, FoG+ exhibited lower beta weights in the cerebellar locomotor region with respect to FoG−. These data support previous results suggesting FoG+ exhibit dysfunction in a number of cortical and subcortical regions, possibly with asymmetric dysfunction towards the right hemisphere. PMID:24595265

  7. Hardware Development and Locomotion Control Strategy for an Over-Ground Gait Trainer: NaTUre-Gaits

    PubMed Central

    Low, Kin Huat; Qu, Xingda; Lim, Hup Boon; Hoon, Kay Hiang

    2014-01-01

    Therapist-assisted body weight supported (TABWS) gait rehabilitation was introduced two decades ago. The benefit of TABWS in functional recovery of walking in spinal cord injury and stroke patients has been demonstrated and reported. However, shortage of therapists, labor-intensiveness, and short duration of training are some limitations of this approach. To overcome these deficiencies, robotic-assisted gait rehabilitation systems have been suggested. These systems have gained attentions from researchers and clinical practitioner in recent years. To achieve the same objective, an over-ground gait rehabilitation system, NaTUre-gaits, was developed at the Nanyang Technological University. The design was based on a clinical approach to provide four main features, which are pelvic motion, body weight support, over-ground walking experience, and lower limb assistance. These features can be achieved by three main modules of NaTUre-gaits: 1) pelvic assistance mechanism, mobile platform, and robotic orthosis. Predefined gait patterns are required for a robotic assisted system to follow. In this paper, the gait pattern planning for NaTUre-gaits was accomplished by an individual-specific gait pattern prediction model. The model generates gait patterns that resemble natural gait patterns of the targeted subjects. The features of NaTUre-gaits have been demonstrated by walking trials with several subjects. The trials have been evaluated by therapists and doctors. The results show that 10-m walking trial with a reduction in manpower. The task-specific repetitive training approach and natural walking gait patterns were also successfully achieved. PMID:27170876

  8. Normal and shear forces between surfaces bearing porcine gastric mucin, a high-molecular-weight glycoprotein.

    PubMed

    Harvey, Neale M; Yakubov, Gleb E; Stokes, Jason R; Klein, Jacob

    2011-04-11

    A surface force balance was used to measure the normal and shear forces between two mica surfaces each bearing an adsorbed layer of porcine gastric mucin ("Orthana" mucin), genetically similar to human MUC6. This mucin is a highly purified, 546 kDa, weakly negative, polyampholytic molecule with a "dumbbell" structure. Both bare (HP) and hydrophobized (HB) mica substrates were used, and forces were measured under 1 and 30 mg/mL mucin solutions, under pure (no-added-salt) water, and under 0.1 M aqueous Na(+) solution. Normal surface forces were monotonically repulsive in all cases, with onset of repulsion occurring at smaller surface separations, D, in the 0.1 M salt solutions (∼ 20 nm, compared with ∼40 nm for no added salt). Repulsion on HP mica was greater on surface compression than decompression, an effect, attributed to bridging and slow-relaxing additional adsorption on compression, not seen on HB mica, a difference attributed to the denser coverage of mucin hydrophobic moieties on the HB surface. Friction forces increased with compression in all cases, showing hysteretic behavior on HP but not on HB mica, commensurate with the hysteresis observed in the normal measurements. Low friction coefficients μ (= ∂F(s)/∂F(n) < 0.05) were seen up to mean pressures

    ≈ 0.5 to 1.0 MPa, attributed to low interpenetration of the opposed layers together with hydration lubrication effects, with higher μ (up to 0.4) at higher

    attributed to interlayer entanglements and to bridging (for the case of HP mica). Shear forces increased only weakly with sliding speed over the range investigated (80-820 nm s(-1)). The lower friction with HB relative to HP mica suggests a selectivity of the HB surface to the hydrophobic moieties of the mucin that in consequence exposes relatively more of the better-lubricating hydrophilic groups. This surface-selectivity effect on lubrication may have a generality extending to other biological macromolecules that contain both hydrophilic and hydrophobic groups. PMID:21341680

  9. Low-cost evaluation and real-time feedback of static and dynamic weight bearing asymmetry in patients undergoing in-patient physiotherapy rehabilitation for neurological conditions

    PubMed Central

    2013-01-01

    Background Weight bearing asymmetry is common in patients with neurological conditions, and recent advances in gaming technology have produced force platforms that are suitable for use in a clinical setting. The aim of this research is to determine whether commercially-available Wii Balance Boards with customized software providing real-time feedback could be used in a clinical setting to evaluate and improve weight-bearing asymmetry in people with various neurological conditions. Methods Twenty participants (age = 43.25 ± 19.37 years) receiving physiotherapy as a result of a neurological condition performed three trials each of two tasks (static standing and sit-to-stand) with and without visual feedback. Vertical forces were measured using available Wii Balance Boards coupled with customized software that displayed visual feedback in real-time. Primary outcome measures included weight-bearing asymmetry as a percentage of body mass, peak force symmetry index, and a visual analogue scale score rating self-perceived level of asymmetry. Results Weight-bearing asymmetry during the static balance task was significantly reduced (Z = −2.912, p = 0.004, ES = 0.65) with visual feedback. There was no significant difference (Z = −0.336, p = 0.737) with visual feedback for the dynamic task, however subgroup analysis indicated that those with higher weight-bearing asymmetry responded the most to feedback. Correlation analysis revealed little or no relationship between participant perception of weight-bearing asymmetry and the results for the static or dynamic balance task (Spearman’s rho: ρ = 0.138, p = 0.561 and ρ = 0.018, ρ =0.940 respectively). Conclusions These findings suggest that weight-bearing asymmetry can be reduced during static tasks in patients with neurological conditions using inexpensive commercially-available Wii Balance Boards coupled with customized visual feedback software. Further research is needed to determine whether real-time visual feedback is appropriate for reducing dynamic weight-bearing asymmetry, whether improvements result in improved physical function, and how cognitive and physical impairments influence the patient’s ability to respond to treatment. PMID:23849318

  10. INFLUENCE OF AGE ON NEUROMUSCULAR CONTROL DURING A DYNAMIC WEIGHT BEARING TASK

    PubMed Central

    Madhavan, Sangeetha; Burkart, Sarah; Baggett, Gail; Nelson, Katie; Teckenburg, Trina; Zwanziger, Mike; Shields, Richard K.

    2009-01-01

    Neuromuscular control strategies may change with age and predispose elderly to knee joint injury. The purposes of this study were to determine if long latency responses (LLR), muscle activation patterns, and movement accuracy differs between the young and elderly during a novel single limb squat (SLS) task. Ten young and ten elderly subjects performed a series of resistive SLS (~0–30 degrees) while matching a computer-generated sinusoidal target. The SLS device provided a 16% body weight resistance to knee movement. Both young and elderly showed significant overshoot error when the knee was perturbed (p < 0.05). Accuracy of the tracking task was similar between the young and elderly (p=0.34), but the elderly required more muscle activity compared to the younger subjects (p < 0.05). The elderly group had larger long latency responses (LLRs) than the younger group (p < 0.05). These results support that neuromuscular control of the knee changes with age, and may contribute to injury. PMID:19799103

  11. THRUST BEARING

    DOEpatents

    Heller, P.R.

    1958-09-16

    A thrust bearing suitable for use with a rotor or blower that is to rotate about a vertical axis is descrihed. A centrifagal jack is provided so thnt the device may opernte on one hearing at starting and lower speeds, and transfer the load to another bearing at higher speeds. A low viscosity fluid is used to lubricate the higher speed operation bearing, in connection with broad hearing -surfaces, the ability to withstand great loads, and a relatively high friction loss, as contraated to the lower speed operatio;n bearing which will withstand only light thrust loads but is sufficiently frictionfree to avoid bearing seizure during slow speed or startup operation. An axially aligned shaft pin provides the bearing surface for low rotational speeds, but at higher speed, weights operating against spring tension withdraw nthe shaft pin into the bearing proper and the rotor shaft comes in contact with the large bearing surfaces.

  12. Evaluation of a bisphosphonate enriched ultra-high molecular weight polyethylene for enhanced total joint replacement bearing surface functionality

    NASA Astrophysics Data System (ADS)

    Wright-Walker, Cassandra Jane

    Each year in the United States there is an increasing trend of patients receiving total joint replacement (TJR) procedures. Approximately a half million total knee replacements (TKRs) are performed annually in the United States with increasing prevalence attributed to baby-boomers, obesity, older, and younger patients. This trend is also seen for total hip replacements (THRs) as well. The use of ultra high molecular weight polyethylene (UHMWPE) inserts in TJRs results in wear particle-induced osteolysis, which is the predominant cause for prosthesis failure and revision surgery. Sub-micron size particle generation is inevitable despite the numerous efforts in improving this bearing material. Work by others has shown that the use of oral and intravenous systemic bisphosphonates (BP) can significantly minimize periprosthetic osteolysis. However, the systemic delivery and the high solubility of BPs results in a predominant portion of the drug being excreted via the kidney without reaching its target, bone. This doctoral research project is focused on the development and evaluation of a novel method to administer BPs locally using the inherent wear of UHMWPE for possible use as an anti-osteolysis treatment. For new materials to be considered, they must be mechanically and tribologically comparable to the current gold standard, UHMWPE. In order to evaluate this material, mechanical, drug elution and tribological experiments were performed to allow assessment of material properties. Tensile tests showed comparable yield stress and pin-on-disk testing showed comparable wear to standard virgin UHMWPE. Further, drug elution tests have shown that BP was released from the enriched material both in static and dynamic conditions. Additionally, an aggressive 2 million cycle total knee simulator experiment has shown statistically similar wear results for the two materials. Overall, this research has provided the groundwork for further characterization and development of a new potential material for total joint replacements as an enhancement to standard UHMWPE. This material shows significant potential as an alternative bearing material to indirectly increase TJR longevity by addressing osteolysis related issues.

  13. Effects of ankle strengthening exercises combined with motor imagery training on the timed up and go test score and weight bearing ratio in stroke patients

    PubMed Central

    Kim, Sung Shin; Lee, Hyung Jin; You, Young Youl

    2015-01-01

    [Purpose] The purpose of the present study was to compare the effects of ankle strengthening exercises combined with motor imagery training and those of ankle strengthening exercises alone in stroke patients. [Subjects and Methods] Thirty stroke patients were randomly assigned to one of the following two groups: experimental group (15 patients) and control group (15 patients). The experimental group underwent motor imagery training for 15 minutes and ankle joint strengthening exercises for 15 minutes, while the control group underwent only ankle joint strengthening exercises for 30 minutes. Each session and training program was implemented four times a week for 4 weeks. The timed up and go (TUG) test score, affected-side weight bearing ratio, and affected-side front/rear weight bearing ratio were assessed. [Results] Both groups demonstrated improvement on the TUG test, and in the affected-side weight bearing ratios, affected-side front/rear weight bearing ratios, and balance errors. The experimental group demonstrated greater improvement than the control group in all variables. [Conclusion] Motor imagery training is an effective treatment method for improving static balance ability in stroke patients. PMID:26311971

  14. Free vascularised osteocutaneous filet flap for covering, that permitted sensitive terminal weight-bearing by a thigh stump after transfemoral amputation.

    PubMed

    Werner, C M L; Exner, G U; Dumont, C E

    2006-01-01

    We covered a transfemoral amputation stump with a modified free filet flap including the calcaneus. The flap survived, resulting in lengthening of the femur, improved distal weight-bearing, preserved sensitivity of the stump, and the design of a prosthesis with terminal loading of the femur rather than an ischial contained prosthesis. PMID:17065124

  15. Multistimuli-responsive supramolecular organogels formed by low-molecular-weight peptides bearing side-chain azobenzene moieties.

    PubMed

    Fatás, Paola; Bachl, Jürgen; Oehm, Stefan; Jiménez, Ana I; Cativiela, Carlos; Díaz Díaz, David

    2013-07-01

    This work demonstrates that the incorporation of azobenzene residues into the side chain of low-molecular-weight peptides can modulate their self-assembly process in organic solvents leading to the formation of stimuli responsive physical organogels. The major driving forces for the gelation process are hydrogen bonding and π-π interactions, which can be triggered either by thermal or ultrasound external stimuli, affording materials having virtually the same properties. In addition, a predictive model for gelation of polar protic solvent was developed by using Kamlet-Taft solvent parameters and experimental data. The obtained viscoelastic materials exhibited interconnected multistimuli responsive behaviors including thermal-, photo-, chemo- and mechanical responses. All of them displayed thermoreversability with gel-to-sol transition temperatures established between 33-80 °C and gelation times from minutes to several hours. Structure-property relationship studies of a designed peptide library have demonstrated that the presence and position of the azobenzene residue can be operated as a versatile regulator to reduce the critical gelation concentration and enhance both the thermal stability and mechanical strength of the gels, as demonstrated by comparative dynamic rheology. The presence of N-Boc protecting group in the peptides showed also a remarkable effect on the formation and properties of the gels. Despite numerous examples of peptide-based gelators known in the literature, this is the first time in which low-molecular-weight peptides bearing side chain azobenzene units are used for the synthesis of "intelligent" supramolecular organogels. Compared with other approaches, this strategy is advantageous in terms of structural flexibility since it is compatible with a free, unprotected amino terminus and allows placement of the chromophore at any position of the peptide sequence. PMID:23704042

  16. A palmar pressure sensor for measurement of upper limb weight bearing by the hands during transfers by paraplegics.

    PubMed

    Kunju, Nissan; Ojha, Rajdeep; Devasahayam, Suresh R

    2013-10-01

    Paraplegic patients have to effect transfer from one seat to another by using their upper limbs. In this process the hands bear almost the entire weight of the body in at least some phases of the transfer. It is desirable to train patients, especially those who are elderly and otherwise weak, to distribute their weight so as to avoid large forces being sustained on any one hand for an extended period. It is also desirable to evaluate the effectiveness of assistive devices like lower limb FES in sharing the load on the hand. This study presents a simple and versatile method of measuring palmar hand force during transfers by paraplegic patients. It is important that this force sensor should not interfere with the grasping and stabilizing properties of the hands and should permit normal transferring. The force sensor comprises an air-filled pouch or pillow that can be placed on any surface. This pneumatic sensor feels like upholstery padding on the surface on which it is placed. The sensor integrates the total pressure applied to the surface of the pouch, thereby obtaining the total force exerted by the palm/hand. The fabrication of the sensor is described, as well as the associated measurement circuit. The static calibration shows that the sensor is linear up to 350 N and the dynamic calibration shows that it has a bandwidth of 13 Hz. The sensor was fabricated using an inflated inelastic airbag attached to a pressure transducer. An automatic offset correction circuit in the preamplifier module ensures that any offset due to initial pressure or sensor drift is removed and the output is zero under no load condition. The key to this sensor arrangement is the ease of fitting it into the intended location without disturbing the existing arrangement for the subject's activities of daily living (ADL). PMID:23964668

  17. Phasic-to-tonic shift in trunk muscle activity relative to walking during low-impact weight bearing exercise

    NASA Astrophysics Data System (ADS)

    Caplan, Nick; Gibbon, Karl; Hibbs, Angela; Evetts, Simon; Debuse, Dorothée

    2014-11-01

    The aim of this study was to investigate the influence of an exercise device, designed to improve the function of lumbopelvic muscles via low-impact weight-bearing exercise, on electromyographic (EMG) activity of lumbopelvic, including abdominal muscles. Surface EMG activity was collected from lumbar multifidus (LM), erector spinae (ES), internal oblique (IO), external oblique (EO) and rectus abdominis (RA) during overground walking (OW) and exercise device (EX) conditions. During walking, most muscles showed peaks in activity which were not seen during EX. Spinal extensors (LM, ES) were more active in EX. Internal oblique and RA were less active in EX. In EX, LM and ES were active for longer than during OW. Conversely, EO and RA were active for a shorter duration in EX than OW. The exercise device showed a phasic-to-tonic shift in activation of both local and global lumbopelvic muscles and promoted increased activation of spinal extensors in relation to walking. These features could make the exercise device a useful rehabilitative tool for populations with lumbopelvic muscle atrophy and dysfunction, including those recovering from deconditioning due to long-term bed rest and microgravity in astronauts.

  18. Instantaneous screws of weight-bearing knee: what can the screws tell us about the knee motion.

    PubMed

    Wolf, Alon

    2014-07-01

    There are several ways to represent a given object's motion in a 3D space having 6DOF i.e., three translations and three rotations. Some of the methods that are used are mathematical and do not provide any geometrical insight into the nature of the motion. Screw theory is a mathematical, while at the same time, geometrical method in which the 6DOF motion of an object can be represented. We describe the 6DOF motion of a weight-bearing knee by its screw parameters, that are extracted from 3D Optical Reflective motion capture data. The screw parameters which describe the transformation of the shank with respect to the thigh in each two successive frames, is represented as the instantaneous screw axis of the motion given in its Plücker line coordinate, along with its corresponding pitch and intensity values. Moreover, the Striction curve associated with the motion provides geometrical insight into the nature of the motion and its repeatability. We describe the theoretical background and demonstrate what the screw can tell us about the motion of healthy subjects' knee. PMID:24599550

  19. Could be the predominantly-used hemibody related to the weight bearing distribution modified by the chronic hemiparesis after stroke?

    PubMed

    Mundim, Anderson Castro; Paz, Clarissa Cardoso dos Santos Couto; Fachin-Martins, Emerson

    2015-11-01

    Since the first Broca publications issued from 1970s, lateralized functions in the human brain have urged the researchers to postulate hypothesis based in the right-left asymmetries and, according to some theories, the lateralization of the voluntary motor control could represent a solution to avoid redundant process optimizing space and time. Supported by this idea, the clinicians and researchers tend to concept that the chronic hemiplegic stroke patients learn to use predominantly the non-affected hemibody after stroke in which is more convenient to execute their daily life activities, modifying their natural preference in some cases. Although could seems reasonable conceptualize the non-affected side as the predominantly-used hemibody for motor tasks after stroke (convenience hypothesis), evidences point to exist also hemiplegic patients that developed a predominantly use of the affected side. To float an idea, in terms of weight bearing distribution during upright position, the researchers have found patients overloading the non-affected hemibody, as expected; but also patients overloading the affected hemibody, not presenting necessarily Pusher's syndrome cases. Given the evidences, we could propose a severity-modulated predominance hypothesis which complements the convenience hypothesis. According to our complementary hypothesis, the severity of the motor disability presented in the hemiparesis condition (light, moderate and heavy severity) could determine a predominant use defined by preference (light to moderate severity) or convenience (moderate to heavy severity). In this hypothesis, we postulate ideas from a rehabilitation perspective to be incorporated in treatment programs. PMID:26305448

  20. Dynamic weight bearing is an efficient and predictable method for evaluation of arthritic nociception and its pathophysiological mechanisms in mice

    PubMed Central

    Quadros, Andreza U.; Pinto, Larissa G.; Fonseca, Miriam M.; Kusuda, Ricardo; Cunha, Fernando Q.; Cunha, Thiago M.

    2015-01-01

    The assessment of articular nociception in experimental animals is a challenge because available methods are limited and subject to investigator influence. In an attempt to solve this problem, the purpose of this study was to establish the use of dynamic weight bearing (DWB) as a new device for evaluating joint nociception in an experimental model of antigen-induced arthritis (AIA) in mice. AIA was induced in Balb/c and C57BL/6 mice, and joint nociception was evaluated by DWB. Western Blotting and real-time PCR were used to determine protein and mRNA expression, respectively. DWB detected a dose- and time-dependent increase in joint nociception during AIA and was able to detect the dose-response effects of different classes of analgesics. Using DWB, it was possible to evaluate the participation of spinal glial cells (microglia and astrocytes) and cytokines (IL-1β and TNFα) for the genesis of joint nociception during AIA. In conclusion, the present results indicated that DWB is an effective, objective and predictable test to study both the pathophysiological mechanisms involved in arthritic nociception in mice and for evaluating novel analgesic drugs against arthritis. PMID:26511791

  1. Recognition using gait.

    SciTech Connect

    Koch, Mark William

    2007-09-01

    Gait or an individual's manner of walking, is one approach for recognizing people at a distance. Studies in psychophysics and medicine indicate that humans can recognize people by their gait and have found twenty-four different components to gait that taken together make it a unique signature. Besides not requiring close sensor contact, gait also does not necessarily require a cooperative subject. Using video data of people walking in different scenarios and environmental conditions we develop and test an algorithm that uses shape and motion to identify people from their gait. The algorithm uses dynamic time warping to match stored templates against an unknown sequence of silhouettes extracted from a person walking. While results under similar constraints and conditions are very good, the algorithm quickly degrades with varying conditions such as surface and clothing.

  2. Effects of weight-bearing activities on bone mineral content and density in children and adolescents: a meta-analysis.

    PubMed

    Behringer, Michael; Gruetzner, Sebastian; McCourt, Molly; Mester, Joachim

    2014-02-01

    Osteoporosis and associated fractures are a major health concern in Western industrialized nations. Exercise during growth is suggested to oppose the involutional bone loss later in life by increasing peak bone mass. The primary aim of the present meta-analysis was to provide a robust estimate of the effect of weight-bearing activities (WBAs) on bone mineral content (BMC) and areal bone mineral density (aBMD), during childhood and adolescence. To locate relevant studies up to June 2012, computerized searches of multiple bibliographic databases and hand searches of key journals and reference lists were performed. Results were extracted by two independent reviewers. The quality of the included trials was assessed via the Physiotherapy Evidence Database (PEDro) score. The study group effect was defined as the difference between the standardized mean change for the treatment and control groups divided by the pooled pretest SD. From 109 potentially relevant studies, only 27 met the inclusion criteria. The analyzed training programs were capable of significantly increasing BMC and aBMD during growth. However, the weighted overall effect sizes (ESs) for changes in BMC (ES 0.17; 95% confidence interval [CI], 0.05-0.29; p < 0.05) and aBMD (ES 0.26; 95% CI, 0.02-0.49) were small. Stepwise backward regression revealed that more than one-third of the observed variance (r(2)  = 0.35) between subgroups of the BMC dataset could be explained by differences in the amount of habitual calcium intake per day (beta 0.54, p < 0.01) and the maturational stage (beta -0.28, p < 0.01) at baseline. No significant moderators were identified for aBMD, possibly due to the small number of trials investigating WBAs on aBMD. The results of this meta-analysis conclude that WBAs alongside high calcium intake provide a practical, relevant method to significantly improve BMC in prepubertal children, justifying the application of this exercise form as an osteoporosis prophylaxis in this stage of maturity. PMID:23857721

  3. Analysis of trotter gait on the track by accelerometry and image analysis.

    PubMed

    Leleu, C; Gloria, E; Renault, G; Barrey, E

    2002-09-01

    The aim of this study was to describe the correlation between the phases of the limb cycle of trotters on the track and specific points on the acceleration curves obtained from a new gait analysis system. We compared kinematic data obtained by video image analysis and 3-dimensional acceleration recordings made on 3 French trotters in training. They trotted on a race track at speeds of 8.33, 10 and 11.66 m/s, with a final stretch at maximum speed. Their locomotion was recorded with a synchronised video camera at a frame frequency of 200 Hz and with the Equimétrix gait analysis system. The gait variables were calculated using 3-dimension acceleration data recorded at the sternum (dorso-ventral, longitudinal and lateral axes) at a sampling rate of 100 Hz. Three phases of the stride were clearly identified on the dorsoventral acceleration signal: hoof-landing, midstance phase and toe-off. Braking and propulsion phases were identified on the corresponding longitudinal acceleration signal. The weight-bearing diagonal was identified by observing the lateral signal. The stride temporal variables (stride, stance, braking and propulsion durations for both diagonals), measured by video analysis and by acceleration signal analysis, were not significantly different (P>0.05). The identification of specific points on the acceleration pattern allowed an accurate temporal analysis of the stride. Potential applications could be the determination of locomotor factors related to racing performance or assessment of locomotor disorders at high speed. PMID:12405713

  4. The effect of patient gait on the material properties of UHMWPE in hip replacements.

    PubMed

    Davey, Shirley M; Orr, John F; Buchanan, Fraser J; Nixon, James R; Bennett, Damien

    2005-08-01

    The wear of ultra-high molecular weight polyethylene (UHMWPE) acetabular components in total hip replacements (THRs) has been shown to be highly dependent on the direction of shear. Greatly reduced wear rates have been reported for unidirectional, compared to multidirectional, articulation in vitro. This work for the first time enables investigation of a relationship between clinical wear conditions, as determined by patient gait path, and the mechanical and structural changes that occur within the UHMWPE acetabular component. Individual patients' wear paths were determined prior to revision operation from hip joint kinematics measured by clinical gait analysis. The material properties of the acetabular components removed during the revision operation were subsequently analysed. A technique using Fourier transform infra- red analysis (FTIR) was developed to quantify the orientation of the individual UHMWPE lamellae. This study shows that there is a direct relationship between a patient's clinical gait path and the molecular properties of their UHMWPE acetabular socket. Patient kinematics are an important factor affecting the wear and long-term biocompatibility of UHMWPE used as a bearing surface in THR. PMID:15769535

  5. Multiple ligament knee reconstruction clinical follow-up and gait analysis.

    PubMed

    Hart, Joseph M; Blanchard, Berkeley F; Hart, Jennifer A; Montgomery, Scott C; Schoderbek, Robert; Miller, Mark D

    2009-03-01

    Multiple ligament knee injuries are serious and rare injures that have not been studied using advanced gait analysis techniques. The purpose of this study was to perform clinical follow-up and gait analysis on patients with multiple knee ligament reconstruction. Twenty-four patients who underwent a multi-ligament knee reconstruction by a single surgeon volunteered to participate in this study. We performed complete clinical exam including instrumented ACL exam (KT-1000), and radiological exam including weight-bearing and PCL stress radiographs (TELOS) at minimum 2 years post index surgery. In addition, we performed complete three-dimensional gait analysis on 18 patients. We used a 10-camera, high speed (120 Hz) motion analysis system in conjunction with a multi-axis strain-gage force plate which calculated knee joint kinetics and kinematics while subjects performed flat-ground walking and stair-descent tasks. Kinematic and kinetic variables were compared between reconstructed and contralateral knees and unmatched, healthy control knees. All knee joint moments were normalized to subjects' weight. Clinical: Average knee joint flexion/extension 123.6 +/- 15.5/1.7 +/- 3.5, respectively. Average KT-1000 side-to-side difference was 1.2 +/- 2.0 mm, TELOS side-to-side difference on stress radiographs was 4.0 +/- 3.1 mm. Median IKDC score was 67 (range 13-94). Fifty-three percent of patients exhibited radiographic evidence of osteoarthritis (OA) on the operative side; one patient on the contralateral knee. During gait analysis, patients exhibited significantly reduced total knee joint range of motion, and external knee flexion moment in the reconstructed knee compared to the contralateral knee and healthy control knees. The magnitude of these differences was greater while descending a step. Finally, patients who had radiographic evidence of knee joint OA had significantly lower magnitude external knee flexion moment compared to those who did not have OA at the time of follow-up. Greater than 2 years after reconstruction, patients with multi-ligament knee injuries are able to return to daily activities. Gait analysis data suggests that patients may be experiencing higher magnitude changes in sagittal plane kinematics and kinetics during demanding functional tasks (stair decent). Changes in walking gait biomechanics may help explain why this group is experiencing unilateral knee joint degeneration. PMID:19107463

  6. Gait or Walking Problems

    MedlinePlus

    Gait or Walking Problems the basic facts multiple sclerosis Many people with MS will experience difficulty with walking, which is also called ambulation. The term “gait” refers more specifically to the manner ...

  7. Balancing the Rates of New Bone Formation and Polymer Degradation Enhances Healing of Weight-Bearing Allograft/Polyurethane Composites in Rabbit Femoral Defects

    PubMed Central

    Dumas, Jerald E.; Prieto, Edna M.; Zienkiewicz, Katarzyna J.; Guda, Teja; Wenke, Joseph C.; Bible, Jesse; Holt, Ginger E.

    2014-01-01

    There is a compelling clinical need for bone grafts with initial bone-like mechanical properties that actively remodel for repair of weight-bearing bone defects, such as fractures of the tibial plateau and vertebrae. However, there is a paucity of studies investigating remodeling of weight-bearing bone grafts in preclinical models, and consequently there is limited understanding of the mechanisms by which these grafts remodel in vivo. In this study, we investigated the effects of the rates of new bone formation, matrix resorption, and polymer degradation on healing of settable weight-bearing polyurethane/allograft composites in a rabbit femoral condyle defect model. The grafts induced progressive healing in vivo, as evidenced by an increase in new bone formation, as well as a decrease in residual allograft and polymer from 6 to 12 weeks. However, the mismatch between the rates of autocatalytic polymer degradation and zero-order (independent of time) new bone formation resulted in incomplete healing in the interior of the composite. Augmentation of the grafts with recombinant human bone morphogenetic protein-2 not only increased the rate of new bone formation, but also altered the degradation mechanism of the polymer to approximate a zero-order process. The consequent matching of the rates of new bone formation and polymer degradation resulted in more extensive healing at later time points in all regions of the graft. These observations underscore the importance of balancing the rates of new bone formation and degradation to promote healing of settable weight-bearing bone grafts that maintain bone-like strength, while actively remodeling. PMID:23941405

  8. Gait Analysis Using Wearable Sensors

    PubMed Central

    Tao, Weijun; Liu, Tao; Zheng, Rencheng; Feng, Hutian

    2012-01-01

    Gait analysis using wearable sensors is an inexpensive, convenient, and efficient manner of providing useful information for multiple health-related applications. As a clinical tool applied in the rehabilitation and diagnosis of medical conditions and sport activities, gait analysis using wearable sensors shows great prospects. The current paper reviews available wearable sensors and ambulatory gait analysis methods based on the various wearable sensors. After an introduction of the gait phases, the principles and features of wearable sensors used in gait analysis are provided. The gait analysis methods based on wearable sensors is divided into gait kinematics, gait kinetics, and electromyography. Studies on the current methods are reviewed, and applications in sports, rehabilitation, and clinical diagnosis are summarized separately. With the development of sensor technology and the analysis method, gait analysis using wearable sensors is expected to play an increasingly important role in clinical applications. PMID:22438763

  9. The effects of ankle mobilization and active stretching on the difference of weight-bearing distribution, low back pain and flexibility in pronated-foots subjects

    PubMed Central

    Yoon, Ki-Seok; Park, Seong-Doo

    2013-01-01

    The purpose of this study was designed to analyze the effects mobilization and active stretching on the difference of weight-bearing distribution, low back pain, and flexibility in pronated-foot subjects. The subjects of this study were 16 chronic low back pain patients. They were randomly divided into the control and experimental group. The experimental group had used the model of ankle mobilization and calf muscle active stretching three times per week, for 4 weeks. The control group did same method without an ankle mobilization. The range of flexion and extension motion of the lumbar vertebrae and low back pain degree and difference of weight-bearing were measured before and after the experiment. The model of ankle mobilization and calf muscle stretching of pronated-foot significantly improved the range of flexion and extension motion of the vertebrae. And the visual analogue scale and distribution of weight-bearing were decreased in both of two groups. In other word, the exercise of this study showed that the model of ankle mobilization and calf muscle stretching of pronated-foot had positive effects on improving the range of flexion and extension motion of the vertebrae. The calf muscle stretching was easy and it is effective in therapy that patients by themselves and helped to recover the balance of the vertebrae to combine ankle mobilization and muscle stretching. PMID:24278874

  10. Gait rehabilitation machines based on programmable footplates

    PubMed Central

    Schmidt, Henning; Werner, Cordula; Bernhardt, Rolf; Hesse, Stefan; Krüger, Jörg

    2007-01-01

    Background Gait restoration is an integral part of rehabilitation of brain lesioned patients. Modern concepts favour a task-specific repetitive approach, i.e. who wants to regain walking has to walk, while tone-inhibiting and gait preparatory manoeuvres had dominated therapy before. Following the first mobilization out of the bed, the wheelchair-bound patient should have the possibility to practise complex gait cycles as soon as possible. Steps in this direction were treadmill training with partial body weight support and most recently gait machines enabling the repetitive training of even surface gait and even of stair climbing. Results With treadmill training harness-secured and partially relieved wheelchair-mobilised patients could practise up to 1000 steps per session for the first time. Controlled trials in stroke and SCI patients, however, failed to show a superior result when compared to walking exercise on the floor. Most likely explanation was the effort for the therapists, e.g. manually setting the paretic limbs during the swing phase resulting in a too little gait intensity. The next steps were gait machines, either consisting of a powered exoskeleton and a treadmill (Lokomat, AutoAmbulator) or an electromechanical solution with the harness secured patient placed on movable foot plates (Gait Trainer GT I). For the latter, a large multi-centre trial with 155 non-ambulatory stroke patients (DEGAS) revealed a superior gait ability and competence in basic activities of living in the experimental group. The HapticWalker continued the end effector concept of movable foot plates, now fully programmable and equipped with 6 DOF force sensors. This device for the first time enables training of arbitrary walking situations, hence not only the simulation of floor walking but also for example of stair climbing and perturbations. Conclusion Locomotor therapy is a fascinating new tool in rehabilitation, which is in line with modern principles of motor relearning promoting a task-specific repetitive approach. Sophisticated technical developments and positive randomized controlled trials form the basis of a growing acceptance worldwide to the benefits or our patients. PMID:17291335

  11. Comparison of Upright Gait with Supine Bungee-Cord Gait

    NASA Technical Reports Server (NTRS)

    Boda, Wanda L.; Hargens, Alan R.; Campbell, J. A.; Yang, C.; Holton, Emily M. (Technical Monitor)

    1998-01-01

    Running on a treadmill with bungee-cord resistance is currently used on the Russian space station MIR as a countermeasure for the loss of bone and muscular strength which occurs during spaceflight. However, it is unknown whether ground reaction force (GRF) at the feet using bungee-cord resistance is similar to that which occurs during upright walking and running on Earth. We hypothesized-that the DRAMs generated during upright walking and running are greater than the DRAMs generated during supine bungee-cord gait. Eleven healthy subjects walked (4.8 +/- 0.13 km/h, mean +/- SE) and ran (9.1 +/- 0.51 km/h) during upright and supine bungee-cord exercise on an active treadmill. Subjects exercised for 3 min in each condition using a resistance of 1 body weight calibrated during an initial, stationary standing position. Data were sampled at a frequency of 500Hz and the mean of 3 trials was analyzed for each condition. A repeated measures analysis of variance tested significance between the conditions. Peak DRAMs during upright walking were significantly greater (1084.9 +/- 111.4 N) than during supine bungee-cord walking (770.3 +/- 59.8 N; p less than 0.05). Peak GRFs were also significantly greater for upright running (1548.3 +/- 135.4 N) than for supine bungee-cord running (1099.5 +/- 158.46 N). Analysis of GRF curves indicated that forces decreased throughout the stance phase for bungee-cord gait but not during upright gait. These results indicate that bungee-cord exercise may not create sufficient loads at the feet to counteract the loss of bone and muscular strength that occurs during long-duration exposure to microgravity.

  12. Magnetic Bearing

    NASA Technical Reports Server (NTRS)

    1996-01-01

    AVCON, Inc. produces advanced magnetic bearing systems for industrial use, offering a unique technological approach based on contract work done at Marshall Space Flight Center and Lewis Research Center. Designed for the turbopump of the Space Shuttle main engine, they are now used in applications such as electric power generation, petroleum refining, machine tool operation and natural gas pipelines. Magnetic bearings support moving machinery without physical contact; AVCON's homopolar approach is a hybrid of permanent and electromagnets which are one-third the weight, smaller and more power- efficient than previous magnetic bearings.

  13. Gait Retraining: Altering the Fingerprint of Gait.

    PubMed

    Davis, Irene S; Futrell, Erin

    2016-02-01

    In terms of running, there is evidence that links mechanics with injury. This evidence provides the justification for altering these mechanics. Increased hip adduction and vertical impact loading have been most commonly associated with injury. More work is needed in order to understand the optimal way to retrain gait patterns in runners. The human body has a considerable ability to adapt. To provide individuals with the ability to alter faulty movement patterns in ways that can reduce injury risk is a powerful tool. PMID:26616188

  14. Validity Of The Nintendo Wii Balance Board To Assess Weight Bearing Asymmetry During Sit-To-Stand And Return-To-Sit Task

    PubMed Central

    Abujaber, Sumayeh; Gillispie, Gregory; Marmon, Adam; Zeni, Joseph

    2015-01-01

    Weight bearing asymmetry is common in patients with unilateral lower limb musculoskeletal pathologies. The Nintendo Wii Balance Board (WBB) has been suggested as a low-cost and widely-available tool to measure weight bearing asymmetry in a clinical environment; however no study has evaluated the validity of this tool during dynamic tasks. Therefore, the purpose of this study was to determine the concurrent validity of force measurements acquired from the WBB as compared to laboratory force plates. Thirty-five individuals before, or within 1 year of total joint arthroplasty performed a sit-to-stand and return-to-sit task in two conditions. First, subjects performed the task with both feet placed on a single WBB. Second, the task was repeated with each foot placed on an individual laboratory force plate. Peak vertical ground reaction force (VGRF) under each foot and the inter-limb symmetry ratio were calculated. Validity was examined using Intraclass Correlation Coefficients (ICC), regression analysis, 95% limits of agreement and Bland-Altman plots. Force plates and the WBB exhibited excellent agreement for all outcome measurements (ICC =0.83–0.99). Bland-Altman plots showed no obvious relationship between the difference and the mean for the peak VGRF, but there was a consistent trend in which VGRF on the unaffected side was lower and VGRF on the affected side was higher when using the WBB. However, these consistent biases can be adjusted for by utilizing regression equations that estimate the force plate values based on the WBB force. The WBB may serve as a valid, suitable, and low-cost alternative to expensive, laboratory force plates for measuring weight bearing asymmetry in clinical settings. PMID:25715680

  15. Validity of the Nintendo Wii Balance Board to assess weight bearing asymmetry during sit-to-stand and return-to-sit task.

    PubMed

    Abujaber, Sumayeh; Gillispie, Gregory; Marmon, Adam; Zeni, Joseph

    2015-02-01

    Weight bearing asymmetry is common in patients with unilateral lower limb musculoskeletal pathologies. The Nintendo Wii Balance Board (WBB) has been suggested as a low-cost and widely-available tool to measure weight bearing asymmetry in a clinical environment; however no study has evaluated the validity of this tool during dynamic tasks. Therefore, the purpose of this study was to determine the concurrent validity of force measurements acquired from the WBB as compared to laboratory force plates. Thirty-five individuals before, or within 1 year of total joint arthroplasty performed a sit-to-stand and return-to-sit task in two conditions. First, subjects performed the task with both feet placed on a single WBB. Second, the task was repeated with each foot placed on an individual laboratory force plate. Peak vertical ground reaction force (VGRF) under each foot and the inter-limb symmetry ratio were calculated. Validity was examined using Intraclass Correlation Coefficients (ICC), regression analysis, 95% limits of agreement and Bland-Altman plots. Force plates and the WBB exhibited excellent agreement for all outcome measurements (ICC=0.83-0.99). Bland-Altman plots showed no obvious relationship between the difference and the mean for the peak VGRF, but there was a consistent trend in which VGRF on the unaffected side was lower and VGRF on the affected side was higher when using the WBB. However, these consistent biases can be adjusted for by utilizing regression equations that estimate the force plate values based on the WBB force. The WBB may serve as a valid, suitable, and low-cost alternative to expensive, laboratory force plates for measuring weight bearing asymmetry in clinical settings. PMID:25715680

  16. A procedure for weighted summation of the derivatives of reflection coefficients in adaptive Schur filter with application to fault detection in rolling element bearings

    NASA Astrophysics Data System (ADS)

    Makowski, Ryszard; Zimroz, Radoslaw

    2013-07-01

    A procedure for feature extraction using adaptive Schur filter for damage detection in rolling element bearings is proposed in the paper. Damaged bearings produce impact signals (shocks) related with local change (loss) of stiffness in pairs: inner/outer race-rolling element. If significant disturbances do not occur (i.e. signal to noise ratio is sufficient), diagnostics is not very complicated and usually envelope analysis is used. Unfortunately, in most industrial examples, these impulsive contributions in vibration are completely masked by noise or other high energy sources. Moreover, impulses may have time varying amplitudes caused by transmission path, load and properties of noise changing in time. Thus, in order to extract time varying signal of interest, the solution would be an adaptive one. The proposed approach is based on the normalized exact least-square time-variant lattice filter (adaptive Schur filter). It is characterized by an extremely fast start-up performance, excellent convergence behavior, and fast parameter tracking capability, making this approach interesting. Schur adaptive filter consists of P sections, estimating, among others, time-varying reflection coefficients (RCs). In this paper it is proposed to use RCs and their derivatives as diagnostic features. However, it is not convenient to analyze simultaneously P signals for P sections, so instead of these, weighted sum of derivatives of RCs can be used. The key question is how to find these weight values for summation procedure. An original contributions are: application of Schur filter to bearings vibration processing, proposal of several features that can be used for detection and mentioned procedure of weighted summation of signal from sections of Schur filter. The method of signal processing is well-adapted for analysis of the non-stationary time-series, so it sounds very promising for diagnostics of machines working in time varying load/speed conditions.

  17. Food intake, tumor growth, and weight loss in EP2 receptor subtype knockout mice bearing PGE2-producing tumors

    PubMed Central

    Iresjö, Britt-Marie; Wang, Wenhua; Nilsberth, Camilla; Andersson, Marianne; Lönnroth, Christina; Smedh, Ulrika

    2015-01-01

    Previous studies in our laboratory have demonstrated that prostaglandin (PG) E2 is involved in anorexia/cachexia development in MCG 101 tumor-bearing mice. In the present study, we investigate the role of PGE receptor subtype EP2 in the development of anorexia after MCG 101 implantation in wild-type (EP2+/+) or EP2-receptor knockout (EP2−/−) mice. Our results showed that host absence of EP2 receptors attenuated tumor growth and development of anorexia in tumor-bearing EP2 knockout mice compared to tumor-bearing wild-type animals. Microarray profiling of the hypothalamus revealed a relative twofold change in expression of around 35 genes including mRNA transcripts coding for Phospholipase A2 and Prostaglandin D2 synthase (Ptgds) in EP2 receptor knockout mice compared to wild-type mice. Prostaglandin D2 synthase levels were increased significantly in EP2 receptor knockouts, suggesting that improved food intake may depend on altered balance of prostaglandin production in hypothalamus since PGE2 and PGD2 display opposing effects in feeding control. PMID:26197930

  18. Predictors of Gait Speed in Patients after Hip Fracture

    PubMed Central

    Craik, Rebecca L.; Lopopolo, Rosalie; Tomlinson, James D.; Brenneman, Susan K.

    2008-01-01

    ABSTRACT Purpose: Following hip fracture, patients demonstrate greatly reduced walking speeds 1 year later compared with age-matched elders. The purpose of our study was to examine the factors that relate to gait speed in patients after hip fracture. Methods: Forty-two men and women (mean age 79 ± 7.5 years) who sustained a hip fracture participated in this study. Linear regression analysis was used to determine a statistical model that best predicted gait speed, the dependent variable. Gait speed was measured with a computerized gait mat. The independent variables were age, sex, height, weight, time post-fracture, medications, mental status, depression, balance confidence, Medical Outcome Studies, Short Form (SF-36), balance, and lower extremity isometric force. All subjects were discharged from physical therapy services, and measurements were taken, on average, 17 weeks post-fracture. Results: Using stepwise regression, 72% of the variance in gait speed was explained by summed lower extremity strength normalized by body weight, general health (SF-36), and balance confidence (Activities-specific Balance Confidence Scale). Conclusions: Impairments (summed lower extremity strength) and risk factors (perception of general health and balance confidence) are important predictors of gait speed in elders after hip fracture. PMID:20145738

  19. Identification of muscle synergies associated with gait transition in humans

    PubMed Central

    Hagio, Shota; Fukuda, Mizuho; Kouzaki, Motoki

    2015-01-01

    There is no theoretical or empirical evidence to suggest how the central nervous system (CNS) controls a variety of muscles associated with gait transition between walking and running. Here, we examined the motor control during a gait transition based on muscle synergies, which modularly organize functionally similar muscles. To this end, the subjects walked or ran on a treadmill and performed a gait transition spontaneously as the treadmill speed increased or decreased (a changing speed condition) or voluntarily following an experimenter’s instruction at constant treadmill speed (a constant speed condition). Surface electromyograms (EMGs) were recorded from 11 lower limb muscles bilaterally. We then extracted the muscle weightings of synergies and their activation coefficients from the EMG data using non-negative matrix factorization. As a result, the gait transition was controlled by approximately 9 muscle synergies, which were common during a walking and running, and their activation profiles were changed before and after a gait transition. Near a gait transition, the peak activation phases of the synergies, which were composed of plantar flexor muscles, were shifted to an earlier phase at the walk-to-run transition, and vice versa. The shifts were gradual in the changing speed condition, but an abrupt change was observed in the constant speed condition. These results suggest that the CNS low-dimensionally regulate the activation profiles of the specific synergies based on afferent information (spontaneous gait transition) or by changing only the descending neural input to the muscle synergies (voluntary gait transition) to achieve a gait transition. PMID:25713525

  20. In vivo regulation of the beta-myosin heavy chain gene in soleus muscle of suspended and weight-bearing rats

    NASA Technical Reports Server (NTRS)

    Giger, J. M.; Haddad, F.; Qin, A. X.; Baldwin, K. M.

    2000-01-01

    In the weight-bearing hindlimb soleus muscle of the rat, approximately 90% of muscle fibers express the beta-myosin heavy chain (beta-MHC) isoform protein. Hindlimb suspension (HS) causes the MHC isoform population to shift from beta toward the fast MHC isoforms. Our aim was to establish a model to test the hypothesis that this shift in expression is transcriptionally regulated through specific cis elements of the beta-MHC promoter. With the use of a direct gene transfer approach, we determined the activity of different length beta-MHC promoter fragments, linked to a firefly luciferase reporter gene, in soleus muscle of control and HS rats. In weight-bearing rats, the relative luciferase activity of the longest beta-promoter fragment (-3500 bp) was threefold higher than the shorter promoter constructs, which suggests that an enhancer sequence is present in the upstream promoter region. After 1 wk of HS, the reporter activities of the -3500-, -914-, and -408-bp promoter constructs were significantly reduced ( approximately 40%), compared with the control muscles. However, using the -215-bp construct, no differences in promoter activity were observed between HS and control muscles, which indicates that the response to HS in the rodent appears to be regulated within the -408 and -215 bp of the promoter.

  1. Effect of Weight-bearing Therapeutic Exercise on the Q-angle and Muscle Activity Onset Times of Elite Athletes with Patellofemoral Pain Syndrome: A Randomized Controlled Trial

    PubMed Central

    Lee, Jehoon; Lee, Hwangjae; Lee, Wanhee

    2014-01-01

    [Purpose] The purpose of this study was to determine the effect of a weight-bearing therapeutic exercise program for elite athletes diagnosed as having patellofemoral pain syndrome (PFPS). [Subjects] The subjects were 34 elite athletes from the Seoul T Center. They were randomly allocated to three groups: an elastic band exercise group (EBG), a sling exercise group (SEG), or a control group (CG). [Methods] Therapeutic exercises were performed 3 times a week for 8 weeks. The visual analogue scale (VAS) hamstring length, and static and dynamic Q angles were used to test the exercise effect of the exercises, as well as the onset time of electromyographic activity of vastus medialis oblique (VMO) and vastus lateralis (VL). [Results] Decrease of the dynamic Q-angle in EBG was significant and significantly greater than that in CG. The decrease in VAS in SEG was significant and significantly greater than that in CG. There were significant differences in the VL and VMO activity onset times in SEG between pre- and post-test, and their differences between pre- and post-test were also significantly different. [Conclusion] Weight-bearing therapeutic exercise is hoped that clinicians will use this information for better implementation of effective exercise methods for elite athletes with PFPS. PMID:25140080

  2. A Moderate-Intensity Weight-Bearing Exercise Program for a Person With Type 2 Diabetes and Peripheral Neuropathy

    PubMed Central

    Hastings, Mary K.; Mueller, Michael J.

    2012-01-01

    Background and Purpose The exercise guidelines for people with diabetes mellitus and peripheral neuropathy (DM+PN) have recently changed to allow moderate-intensity weight-bearing exercise, but there are few reports in the literature describing appropriate weight-bearing exercise for those with DM+PN. This case report describes a successful and safe progressive exercise program for an individual with DM+PN. Case Description The patient was a 76-year-old man with a 30-year history of DM+PN. He participated in a 12-week, moderate-intensity, progressive exercise program (heart rate approximately 75% of maximum heart rate; rate of perceived exertion=11–13; 3 times per week) involving walking on a treadmill, balance exercises, and strengthening exercises for the lower extremities using body weight resistance. Outcomes Measurements were taken before and after the 12 weeks of exercise. The patient's Six-Minute Walk Test distance increased from 1,200 to 1,470 ft. His Physical Performance Test score did not change. His Foot and Ankle Ability Measure questionnaire score improved from 89 to 98. Dorsiflexor and plantar-flexor peak torque increased (dorsiflexor peak torque: right side=4.5–4.6 N·m, left side=2.8–3.8 N·m; plantar-flexor peak torque: right side=44.7–62.4 N·m, left side=40.8–56.0 N·m), as did his average daily step count (6,176–8,273 steps/day). Close monitoring of the plantar surface of the feet indicated that the exercise program was well tolerated and there were no adverse events. Discussion and Conclusions This case report describes a moderate-intensity exercise program that was successful in increasing some measures of muscle strength, physical function, and activity without causing injury in an individual with DM+PN. PMID:21921252

  3. Effective one step-iterative fiducial marker-based compensation for involuntary motion in weight-bearing C-arm cone-beam CT scanning of knees

    NASA Astrophysics Data System (ADS)

    Choi, Jang-Hwan; Maier, Andreas; Berger, Martin; Fahrig, Rebecca

    2014-03-01

    We previously introduced three different fiducial marker-based correction methods (2D projection shifting, 2D projection warping, and 3D image warping) for patients' involuntary motion in the lower body during weight-bearing Carm CT scanning. The 3D warping method performed better than 2D methods since it could more accurately take into account the lower body motion in 3D. However, as the 3D warping method applies different rotational and translational movement to the reconstructed image for each projection frame, distance-related weightings were slightly twisted and thus result in overlaying background noise over the entire image. In order to suppress background noise and artifacts (e.g. metallic marker-caused streaks), the 3D warping method has been improved by incorporating bilateral filtering and a Landwebertype iteration in one step. A series of projection images of five healthy volunteers standing at various flexion angles were acquired using a C-arm cone-beam CT system with a flat panel. A horizontal scanning trajectory of the C-arm was calibrated to generate projection matrices. Using the projection matrices, the static reference marker coordinates in 3D were estimated and used for the improved 3D warping method. The improved 3D warping method effectively reduced background noise down below the noise level of 2D methods and also eliminated metal-generated streaks. Thus, improved visibility of soft tissue structures (e.g. fat and muscle) was achieved while maintaining sharp edges at bone-tissue interfaces. Any high resolution weight-bearing cone-beam CT system can apply this method for motion compensation.

  4. Growth hormone, IGF-I, and exercise effects on non-weight-bearing fast muscles of hypophysectomized rats

    NASA Technical Reports Server (NTRS)

    Grossman, E. J.; Grindeland, R. E.; Roy, R. R.; Talmadge, R. J.; Evans, J.; Edgerton, V. R.

    1997-01-01

    The effects of growth hormone (GH) or insulin-like growth factor I (IGF-I) with or without exercise (ladder climbing) in countering the effects of unweighting on fast muscles of hypophysectomized rats during 10 days of hindlimb suspension were determined. Compared with untreated suspended rats, muscle weights were 16-29% larger in GH-treated and 5-15% larger in IGF-I-treated suspended rats. Exercise alone had no effect on muscle weights. Compared with ambulatory control, the medial gastrocnemius weight in suspended, exercised rats was larger after GH treatment and maintained with IGF-I treatment. The combination of GH or IGF-I plus exercise in suspended rats resulted in an increase in size of each predominant fiber type, i.e., types I, I + IIa and IIa + IIx, in the medial gastrocnemius compared with untreated suspended rats. Normal ambulation or exercise during suspension increased the proportion of fibers expressing embryonic myosin heavy chain in hypophysectomized rats. The phenotype of the medial gastrocnemius was minimally affected by GH, IGF-I, and/or exercise. These results show that there is an IGF-I, as well as a GH, and exercise interactive effect in maintaining medial gastrocnemius fiber size in suspended hypophysectomized rats.

  5. Proteomic analysis profile of engineered articular cartilage with chondrogenic differentiated adipose tissue-derived stem cells loaded polyglycolic acid mesh for weight-bearing area defect repair.

    PubMed

    Gong, Lunli; Zhou, Xiao; Wu, Yaohao; Zhang, Yun; Wang, Chen; Zhou, Heng; Guo, Fangfang; Cui, Lei

    2014-02-01

    The present study was designed to investigate the possibility of full-thickness defects repair in porcine articular cartilage (AC) weight-bearing area using chondrogenic differentiated autologous adipose-derived stem cells (ASCs) with a follow-up of 3 and 6 months, which is successive to our previous study on nonweight-bearing area. The isolated ASCs were seeded onto the phosphoglycerate/polylactic acid (PGA/PLA) with chondrogenic induction in vitro for 2 weeks as the experimental group prior to implantation in porcine AC defects (8 mm in diameter, deep to subchondral bone), with PGA/PLA only as control. With follow-up time being 3 and 6 months, both neo-cartilages of postimplantation integrated well with the neighboring normal cartilage and subchondral bone histologically in experimental group, whereas only fibrous tissue in control group. Immunohistochemical and toluidine blue staining confirmed similar distribution of COL II and glycosaminoglycan in the regenerated cartilage to the native one. A vivid remolding process with repair time was also witnessed in the neo-cartilage as the compressive modulus significantly increased from 70% of the normal cartilage at 3 months to nearly 90% at 6 months, which is similar to our former research. Nevertheless, differences of the regenerated cartilages still could be detected from the native one. Meanwhile, the exact mechanism involved in chondrogenic differentiation from ASCs seeded on PGA/PLA is still unknown. Therefore, proteome is resorted leading to 43 proteins differentially identified from 20 chosen two-dimensional spots, which do help us further our research on some committed factors. In conclusion, the comparison via proteome provided a thorough understanding of mechanisms implicating ASC differentiation toward chondrocytes, which is further substantiated by the present study as a perfect supplement to the former one in nonweight-bearing area. PMID:24044689

  6. Gait in Very Preterm School-Aged Children in Dual-Task Paradigms

    PubMed Central

    Hagmann-von Arx, Priska; Manicolo, Olivia; Perkinson-Gloor, Nadine; Weber, Peter; Grob, Alexander; Lemola, Sakari

    2015-01-01

    Objective The control of gait requires executive and attentional functions. As preterm children show executive and attentional deficits compared to full-term children, performing concurrent tasks that impose additional cognitive load may lead to poorer walking performance in preterm compared to full-term children. Knowledge regarding gait in preterm children after early childhood is scarce. We examined straight walking and if it is more affected in very preterm than in full-term children in dual-task paradigms. Study design Twenty preterm children with very low birth-weight (≤ 1500 g), 24 preterm children with birth-weight > 1500 g, and 44 full-term children, born between 2001 and 2006, were investigated. Gait was assessed using an electronic walkway system (GAITRite) while walking without a concurrent task (single-task) and while performing one concurrent (dual-task) or two concurrent (triple-task) tasks. Spatio-temporal gait parameters (gait velocity, cadence, stride length, single support time, double support time), normalized gait parameters (normalized velocity, normalized cadence, normalized stride length) and gait variability parameters (stride velocity variability, stride length variability) were analyzed. Results In dual- and triple-task conditions children showed decreased gait velocity, cadence, stride length, as well as increased single support time, double support time and gait variability compared to single-task walking. Further, results showed systematic decreases in stride velocity variability from preterm children with very low birth weight (≤ 1500 g) to preterm children with birth weight > 1500 g to full-term children. There were no significant interactions between walking conditions and prematurity status. Conclusions Dual and triple tasking affects gait of preterm and full-term children, confirming previous results that walking requires executive and attentional functions. Birth-weight dependent systematic changes in stride velocity variability indicate poorer walking performance in preterm children who were less mature at birth. PMID:26641492

  7. Gait Recognition and Walking Exercise Intensity Estimation

    PubMed Central

    Lin, Bor-Shing; Liu, Yu-Ting; Yu, Chu; Jan, Gene Eu; Hsiao, Bo-Tang

    2014-01-01

    Cardiovascular patients consult doctors for advice regarding regular exercise, whereas obese patients must self-manage their weight. Because a system for permanently monitoring and tracking patients’ exercise intensities and workouts is necessary, a system for recognizing gait and estimating walking exercise intensity was proposed. For gait recognition analysis, αβ filters were used to improve the recognition of athletic attitude. Furthermore, empirical mode decomposition (EMD) was used to filter the noise of patients’ attitude to acquire the Fourier transform energy spectrum. Linear discriminant analysis was then applied to this energy spectrum for training and recognition. When the gait or motion was recognized, the walking exercise intensity was estimated. In addition, this study addressed the correlation between inertia and exercise intensity by using the residual function of the EMD and quadratic approximation to filter the effect of the baseline drift integral of the acceleration sensor. The increase in the determination coefficient of the regression equation from 0.55 to 0.81 proved that the accuracy of the method for estimating walking exercise intensity proposed by Kurihara was improved in this study. PMID:24714057

  8. Biology of gait control

    PubMed Central

    Annweiler, C.; Verghese, J.; Fantino, B.; Herrmann, F.R.; Allali, G.

    2011-01-01

    Background: Adverse neuromuscular events have been described in case of low serum 25-hydroxyvitamin D (25OHD) concentrations, suggesting that vitamin D may be involved in gait stability. The objective of this cross-sectional study was to examine the association between stride-to-stride variability of stride time (STV) and serum 25OHD concentration in adults aged 65 years and older. Methods: STV and 25OHD concentration were assessed in 411 community-dwelling older adults (mean age 70.4 1.8 years, 57.9% women). The following established 25OHD thresholds were used: severe 25OHD insufficiency <10 ng/mL, moderate 1030 ng/mL, and normal >30 ng/mL. Age, number of drugs used per day, use of psychoactive drugs, depressive symptoms, cognitive decline, history of falls, distance visual acuity, lower limb proprioception, center of mass (CoM) motion, and walking speed were considered as potential confounders. Results: A total of 16.6% (n = 68) of subjects had severe 25OHD insufficiency, 70.3% (n = 289) moderate insufficiency, and 13.1% (n = 54) normal concentrations. In the full adjusted and the stepwise backward linear regression models, high STV (worse performance) was associated with severe 25OHD insufficiency (p = 0.028 and p = 0.044, respectively), high CoM motion (p = 0.031 and p = 0.014, respectively), and low lower limb proprioception score (p = 0.017 and p = 0.008, respectively). The stepwise backward regression model also showed that high STV was associated with female gender (p = 0.041). Conclusions: Low serum 25OHD concentrations were associated with high STV reflecting a disturbed gait control. This association could be explained by a possible action of vitamin D on different components involved in gait control. PMID:21471466

  9. Geometric moments for gait description

    NASA Astrophysics Data System (ADS)

    Toxqui-Quitl, C.; Morales-Batalla, V.; Padilla-Vivanco, A.; Camacho-Bello, C.

    2013-09-01

    The optical flow associated with a set of digital images of a moving individual is analyzed in order to extract a gait signature. For this, invariant Hu moments are obtained for image description. A Hu Moment History (HMH) is obtained from K frames to describe the gait signature of individuals in a video. The gait descriptors are subsequences of the HMH of variable width. Each subsequence is generated by means of genetic algorithms and used for classification in a neuronal network. The database for algorithm evaluation is MoBo, and the gait classification results are above 90% for the cases of slow and fast walking and 100% for the cases of walking with a ball and inclined walking. An optical processor is also implemented in order to obtain the descriptors of the human gait.

  10. Pioglitazone Treatment Increases Survival and Prevents Body Weight Loss in Tumor–Bearing Animals: Possible Anti-Cachectic Effect

    PubMed Central

    Beluzi, Mércia; Peres, Sidney B.; Henriques, Felipe S.; Sertié, Rogério A. L.; Franco, Felipe O.; Santos, Kaltinaitis B.; Knobl, Pâmela; Andreotti, Sandra; Shida, Cláudio S.; Neves, Rodrigo X.; Farmer, Stephen R.; Seelaender, Marília; Lima, Fábio B.; Batista Jr., Miguel L.

    2015-01-01

    Cachexia is a multifactorial syndrome characterized by profound involuntary weight loss, fat depletion, skeletal muscle wasting, and asthenia; all symptoms are not entirely attributable to inadequate nutritional intake. Adipose tissue and skeletal muscle loss during cancer cachexia development has been described systematically. The former was proposed to precede and be more rapid than the latter, which presents a means for the early detection of cachexia in cancer patients. Recently, pioglitazone (PGZ) was proposed to exhibit anti-cancer properties, including a reduction in insulin resistance and adipose tissue loss; nevertheless, few studies have evaluated its effect on survival. For greater insight into a potential anti-cachectic effect due to PGZ, 8-week-old male Wistar rats were subcutaneously inoculated with 1 mL (2×107) of Walker 256 tumor cells. The animals were randomly assigned to two experimental groups: TC (tumor + saline-control) and TP5 (tumor + PGZ/5 mg). Body weight, food ingestion and tumor growth were measured at baseline and after removal of tumor on days 7, 14 and 26. Samples from different visceral adipose tissue (AT) depots were collected on days 7 and 14 and stored at -80o C (5 to 7 animals per day/group). The PGZ treatment showed an increase in the survival average of 27.3% (P< 0.01) when compared to TC. It was also associated with enhanced body mass preservation (40.7 and 56.3%, p< 0.01) on day 14 and 26 compared with the TC group. The treatment also reduced the final tumor mass (53.4%, p<0.05) and anorexia compared with the TC group during late-stage cachexia. The retroperitoneal AT (RPAT) mass was preserved on day 7 compared with the TC group during the same experimental period. Such effect also demonstrates inverse relationship with tumor growth, on day 14. Gene expression of PPAR-γ, adiponectin, LPL and C/EBP-α from cachectic rats was upregulated after PGZ. Glucose uptake from adipocyte cells (RPAT) was entirely re-established due to PGZ treatment. Taken together, the results demonstrate beneficial effects of PGZ treatment at both the early and final stages of cachexia. PMID:25807446

  11. The effect of kinematic conditions on the wear of ultra-high molecular weight polyethylene (UHMWPE) in orthopaedic bearing applications.

    PubMed

    Cornwall, G B; Bryant, J T; Hansson, C M

    2001-01-01

    It is known that wear mechanisms differ between the ultra-high molecular weight polyethylene (UHMWPE) components of total hip replacement (THR) and total knee replacement (TKR). The difference in relative contact position or 'kinematic conditions of contact' between the metal and polymer components is thought to contribute to the contrast in observed wear mechanisms. A reciprocating wear tester was used to evaluate three basic kinematic contact conditions: sliding, in which the relative contact position on the polymer remains stationary; gliding, where the contact position on the polymer reciprocates; and rolling, where the contact position on the polymer varies and the relative velocities of both components are equal. All static load tests used cast Co-Cr alloy and irradiated Chirulen UHMWPE in a 37 degrees C environment lubricated with bovine serum albumin. UHMWPE test sample wear was measured gravimetrically at intervals of 600,000 cycles. The results indicated a difference in wear factor (volume lost due to wear per unit load per unit sliding distance) between the three groups with varying relative motion. The study indicates that screening tests which evaluate wear properties of new materials for total joint replacement should reflect the different kinematic contact conditions. PMID:11323990

  12. Effects of acceleration on gait measures in three horse gaits.

    PubMed

    Nauwelaerts, Sandra; Zarski, Lila; Aerts, Peter; Clayton, Hilary

    2015-05-01

    Animals switch gaits according to locomotor speed. In terrestrial locomotion, gaits have been defined according to footfall patterns or differences in center of mass (COM) motion, which characterizes mechanisms that are more general and more predictive than footfall patterns. This has generated different variables designed primarily to evaluate steady-speed locomotion, which is easier to standardize in laboratory conditions. However, in the ecology of an animal, steady-state conditions are rare and the ability to accelerate, decelerate and turn is essential. Currently, there are no data available that have tested whether COM variables can be used in accelerative or decelerative conditions. This study used a data set of kinematics and kinetics of horses using three gaits (walk, trot, canter) to evaluate the effects of acceleration (both positive and negative) on commonly used gait descriptors. The goal was to identify variables that distinguish between gaits both at steady state and during acceleration/deceleration. These variables will either be unaffected by acceleration or affected by it in a predictable way. Congruity, phase shift and COM velocity angle did not distinguish between gaits when the dataset included trials in unsteady conditions. Work (positive and negative) and energy recovery distinguished between gaits and showed a clear relationship with acceleration. Hodographs are interesting graphical representations to study COM mechanics, but they are descriptive rather than quantitative. Force angle, collision angle and collision fraction showed a U-shaped relationship with acceleration and seem promising tools for future research in unsteady conditions. PMID:25767145

  13. [Development of a gait trainer with regulated servo-drive for rehabilitation of locomotor disabled patients].

    PubMed

    Uhlenbrock, D; Sarkodie-Gyan, T; Reiter, F; Konrad, M; Hesse, S

    1997-01-01

    The aim of the present study was to develop a new gait trainer for the rehabilitation of non-ambulatory patients. For the simulation of the gait phase, we used a commercially available fitness trainer (Fast Track) with two foot plates moving in an alternating fashion and connected to a servo-controlled propulsion system providing the necessary support for the movement depending on the patient's impairment level. To compensate deficient equilibrium reflexes, the patient was suspended in a harness capable of supporting some of his/her weight. Video analysis of gait and the kinesiological EMG were used to assess the pattern of movement and the corresponding muscle activity, which were then evaluated in healthy subjects, spinal cord injured and stroke patients and compared with walking on the flat or on a treadmill. Walking on the gait trainer was characterised by a symmetrical, sinusoidal movement of lower amplitude than in normal gait. The EMG showed a low activity of the tibialis anterior muscle, while the antigravity muscles were clearly activated by the gait trainer during the stance phase. In summary, the new gait trainer generates a symmetrical gait-like movement, promoting weight acceptance in the stance phase, which is important for the restoration of walking ability. PMID:9376497

  14. Heritability and Genome-Wide Association Analyses of Human Gait Suggest Contribution of Common Variants.

    PubMed

    Adams, Hieab H H; Verlinden, Vincentius J A; Callisaya, Michele L; van Duijn, Cornelia M; Hofman, Albert; Thomson, Russell; Uitterlinden, André G; Vernooij, Meike W; van der Geest, Jos N; Srikanth, Velandai; Ikram, M Arfan

    2016-06-01

    Human gait is a complex neurological and musculoskeletal function, of which the genetic basis remains largely unknown. To determine the influence of common genetic variants on gait parameters, we studied 2,946 participants of the Rotterdam Study, a population-based cohort of unrelated elderly individuals. We assessed 30 gait parameters using an electronic walkway, which yielded seven independent gait domains after principal component analysis. Genotypes of participants were imputed to the 1,000 Genomes reference panel for generating genetic relationship matrices to estimate heritability of gait parameters, and for subsequent genome-wide association scans (GWASs) to identify specific variants. Gait domains with the highest age- and sex-adjusted heritability were Variability (h (2) = 61%), Rhythm (37%), and Tandem (32%). For other gait domains, heritability estimates attenuated after adjustment for height and weight. Genome-wide association scans identified a variant on 1p22.3 that was significantly associated with single support time, a variable from the Rhythm domain (rs72953990; N = 2,946; β [SE] = 0.0069 (0.0012), p = 2.30×10(-8)). This variant did not replicate in an independent sample (N = 362; p = .78). In conclusion, human gait has highly heritable components that are explained by common genetic variation, which are partly attributed to height and weight. Collaborative efforts are needed to identify robust single variant associations for the heritable parameters. PMID:26219847

  15. The relationship between spatiotemporal gait asymmetry and balance in individuals with chronic stroke.

    PubMed

    Lewek, Michael D; Bradley, Claire E; Wutzke, Clinton J; Zinder, Steven M

    2014-02-01

    Falls are common after stroke and often attributed to poor balance. Falls often occur during walking, suggesting that walking patterns may induce a loss of balance. Gait after stroke is frequently spatiotemporally asymmetric, which may decrease balance. The purpose of this study is to determine the relationship between spatiotemporal gait asymmetry and balance control. Thirty-nine individuals with chronic stroke walked at comfortable and fast speeds to calculate asymmetry ratios for step length, stance time, and swing time. Balance measures included the Berg Balance Scale, step width during gait, and the weight distribution between legs during standing. Correlational analyses determined the relationships between balance and gait asymmetry. At comfortable and fast gait speeds, step width was correlated with stance time and swing time asymmetries (r = 0.39-0.54). Berg scores were correlated with step length and swing time asymmetries (r = -0.36 to -0.63). During fast walking, the weight distribution between limbs was correlated with stance time asymmetry (r = -0.41). Spatiotemporal gait asymmetry was more closely related to balance measures involving dynamic tasks than static tasks, suggesting that gait asymmetry may be related to the high number of falls poststroke. Further study to determine if rehabilitation that improves gait asymmetry has a similar influence on balance is warranted. PMID:23677889

  16. Fiducial marker-based correction for involuntary motion in weight-bearing C-arm CT scanning of knees. II. Experiment

    PubMed Central

    Choi, Jang-Hwan; Maier, Andreas; Keil, Andreas; Pal, Saikat; McWalter, Emily J.; Beaupré, Gary S.; Gold, Garry E.; Fahrig, Rebecca

    2014-01-01

    Purpose: A C-arm CT system has been shown to be capable of scanning a single cadaver leg under loaded conditions by virtue of its highly flexible acquisition trajectories. In Part I of this study, using the 4D XCAT-based numerical simulation, the authors predicted that the involuntary motion in the lower body of subjects in weight-bearing positions would seriously degrade image quality and the authors suggested three motion compensation methods by which the reconstructions could be corrected to provide diagnostic image quality. Here, the authors demonstrate that a flat-panel angiography system is appropriate for scanning both legs of subjects in vivo under weight-bearing conditions and further evaluate the three motion-correction algorithms using in vivo data. Methods: The geometry of a C-arm CT system for a horizontal scan trajectory was calibrated using the PDS-2 phantom. The authors acquired images of two healthy volunteers while lying supine on a table, standing, and squatting at several knee flexion angles. In order to identify the involuntary motion of the lower body, nine 1-mm-diameter tantalum fiducial markers were attached around the knee. The static mean marker position in 3D, a reference for motion compensation, was estimated by back-projecting detected markers in multiple projections using calibrated projection matrices and identifying the intersection points in 3D of the back-projected rays. Motion was corrected using three different methods (described in detail previously): (1) 2D projection shifting, (2) 2D deformable projection warping, and (3) 3D rigid body warping. For quantitative image quality analysis, SSIM indices for the three methods were compared using the supine data as a ground truth. Results: A 2D Euclidean distance-based metric of subjects’ motion ranged from 0.85 mm (±0.49 mm) to 3.82 mm (±2.91 mm) (corresponding to 2.76 to 12.41 pixels) resulting in severe motion artifacts in 3D reconstructions. Shifting in 2D, 2D warping, and 3D warping improved the SSIM in the central slice by 20.22%, 16.83%, and 25.77% in the data with the largest motion among the five datasets (SCAN5); improvement in off-center slices was 18.94%, 29.14%, and 36.08%, respectively. Conclusions: The authors showed that C-arm CT control can be implemented for nonstandard horizontal trajectories which enabled us to scan and successfully reconstruct both legs of volunteers in weight-bearing positions. As predicted using theoretical models, the proposed motion correction methods improved image quality by reducing motion artifacts in reconstructions; 3D warping performed better than the 2D methods, especially in off-center slices. PMID:24877813

  17. Fiducial marker-based correction for involuntary motion in weight-bearing C-arm CT scanning of knees. II. Experiment

    SciTech Connect

    Choi, Jang-Hwan; Maier, Andreas; Keil, Andreas; McWalter, Emily J.; Gold, Garry E.; Fahrig, Rebecca; Pal, Saikat; Beaupré, Gary S.

    2014-06-15

    Purpose: A C-arm CT system has been shown to be capable of scanning a single cadaver leg under loaded conditions by virtue of its highly flexible acquisition trajectories. In Part I of this study, using the 4D XCAT-based numerical simulation, the authors predicted that the involuntary motion in the lower body of subjects in weight-bearing positions would seriously degrade image quality and the authors suggested three motion compensation methods by which the reconstructions could be corrected to provide diagnostic image quality. Here, the authors demonstrate that a flat-panel angiography system is appropriate for scanning both legs of subjectsin vivo under weight-bearing conditions and further evaluate the three motion-correction algorithms using in vivo data. Methods: The geometry of a C-arm CT system for a horizontal scan trajectory was calibrated using the PDS-2 phantom. The authors acquired images of two healthy volunteers while lying supine on a table, standing, and squatting at several knee flexion angles. In order to identify the involuntary motion of the lower body, nine 1-mm-diameter tantalum fiducial markers were attached around the knee. The static mean marker position in 3D, a reference for motion compensation, was estimated by back-projecting detected markers in multiple projections using calibrated projection matrices and identifying the intersection points in 3D of the back-projected rays. Motion was corrected using three different methods (described in detail previously): (1) 2D projection shifting, (2) 2D deformable projection warping, and (3) 3D rigid body warping. For quantitative image quality analysis, SSIM indices for the three methods were compared using the supine data as a ground truth. Results: A 2D Euclidean distance-based metric of subjects’ motion ranged from 0.85 mm (±0.49 mm) to 3.82 mm (±2.91 mm) (corresponding to 2.76 to 12.41 pixels) resulting in severe motion artifacts in 3D reconstructions. Shifting in 2D, 2D warping, and 3D warping improved the SSIM in the central slice by 20.22%, 16.83%, and 25.77% in the data with the largest motion among the five datasets (SCAN5); improvement in off-center slices was 18.94%, 29.14%, and 36.08%, respectively. Conclusions: The authors showed that C-arm CT control can be implemented for nonstandard horizontal trajectories which enabled us to scan and successfully reconstruct both legs of volunteers in weight-bearing positions. As predicted using theoretical models, the proposed motion correction methods improved image quality by reducing motion artifacts in reconstructions; 3D warping performed better than the 2D methods, especially in off-center slices.

  18. Postural stability in symmetrical gaits.

    PubMed

    Zielińska, Teresa; Trojnacki, Maciej

    2009-01-01

    In this paper the method of stability analysis of dynamic symmetrical gaits is discussed. The problem of dynamic postural equilibrium, taking into account the role of compliant feet, is solved. The equilibrium conditions are split between the foot attachment points and the points within the foot-end area. The present method is useful for motion synthesis, taking into account robot parameters. It also helps in the robot foot design. As an illustrative example a four-legged diagonal gait is considered. The theoretical results were verified by implementing and observing the diagonal gait in four-legged machine with and without feet. PMID:19839558

  19. Longitudinal relationships between whole body and central adiposity on weight-bearing bone geometry, density, and bone strength: a pQCT study in young girls

    PubMed Central

    Farr, Joshua N.; Laudermilk, Monica J.; Lee, Vinson R.; Blew, Robert M.; Stump, Craig; Houtkooper, Linda; Lohman, Timothy G.; Going, Scott B.

    2015-01-01

    Summary Longitudinal relationships between adiposity (total body and central) and bone development were assessed in young girls. Total body and android fat masses were positively associated with bone strength and density parameters of the femur and tibia. These results suggest adiposity may have site-specific stimulating effects on the developing bone. Introduction Childhood obesity may impair bone development, but the relationships between adiposity and bone remain unclear. Failure to account for fat pattern may explain the conflicting results. Purpose Longitudinal associations of total body fat mass (TBFM) and android fat mass (AFM) with 2-year changes in weight-bearing bone parameters were examined in 260 girls aged 8–13 years at baseline. Peripheral quantitative computed tomography was used to measure bone strength index (BSI, square milligrams per quartic millimeter), strength–strain index (SSI, cubic millimeters), and volumetric bone mineral density (vBMD, milligrams per cubic centimeter) at distal metaphyseal and diaphyseal regions of the femur and tibia. TBFM and AFM were assessed by dual-energy x-ray absorptiometry. Results Baseline TBFM and AFM were positively associated with the change in femur BSI (r =0.20, r =0.17, respectively) and femur trabecular vBMD (r =0.19, r =0.19, respectively). Similarly, positive associations were found between TBFM and change in tibia BSI and SSI (r =0.16, r =0.15, respectively), and femur total and trabecular vBMD (r =0.12, r =0.14, respectively). Analysis of covariance showed that girls in the middle thirds of AFM had significantly lower femur trabecular vBMD and significantly higher tibia cortical vBMD than girls in the highest thirds of AFM. All results were significant at p <0.05. Conclusions Whereas baseline levels of TBFM and AFM are positive predictors of bone strength and density at the femur and tibia, higher levels of AFM above a certain level may impair cortical vBMD growth at weight-bearing sites. Future studies in obese children will be needed to test this possibility. NIH/NICHD #HD-050775. PMID:24113839

  20. Gait epilepsy. A case report of gait-induced seizures.

    PubMed

    Iriarte, J; Sánchez-Carpintero, R; Schlumberger, E; Narbona, J; Viteri, C; Artieda, J

    2001-08-01

    Reflex epilepsy includes a group of epileptic syndromes in which seizures are induced by a stimulus, either simple (visual, somatosensory, olfactory, auditory) or more complex (e.g., eating, thinking, reading). We document a case of reflex epilepsy in which focal seizures are triggered exclusively by gait. The patient is a young boy whose walking was impaired by abnormal motor phenomena on the left side. These phenomena were elicited by gait and were accompanied by a distinctive ictal pattern with centro-temporal discharges. After comparing this patient with others reported in the literature, we determined that he has an unusual type of reflex epilepsy for which we coined the term "gait epilepsy." This disorder must be considered when physicians are making a differential diagnosis in patients who have symptoms that suggest paroxysmal kinesigenic dystonia (PKD) or selective epileptic gait disorder. PMID:11554899

  1. Rehabilitation of gait in patients after total hip arthroplasty: Comparison of the minimal invasive Yale 2-incision technique and the conventional lateral approach.

    PubMed

    Böhm, Harald; Hagemeyer, Daniel; Thummerer, Yvonne; Kipping, Robert; Stöckle, Ulrich; Scheuerer, Konrad

    2016-02-01

    The minimal invasive anterolateral Yale 2-incision approach for total hip arthroplasty aims minimizing damage to the muscles for faster recovery of function. Therefore the hypothesis was investigated, that during the rehabilitation process the Yale approach shows a faster return to natural gait than a conventional lateral approach. Nineteen patients had the Yale, 16 the conventional Bauer approach. Instrumented gait analysis was performed 3 days, 3 and 12 month post operatively. Velocity, cadence, step length, weight bearing, thorax lean, Trendelenburg limp, hip abduction moments, and hip muscle activation times were evaluated. Three days post-surgery a significantly greater loading of the treated limb and increased hip abduction moment were observed in the Yale group. In addition, the Yale group showed its greatest improvement in walking speed and step length between at 3 days and 3 months, whereas the conventional group showed an additional significant gain between 3 and 12 month to reach a similar walking speed as the Yale group. For all hip muscles investigated, only muscle tensor fasciae latae in the conventional group showed a significant increase in activation time between 3 days and 3 months. This study showed significantly faster return to natural gait in the Yale compared to the conventional approach, which could be biomechanically related to less impairment of abductor muscles in the Yale approach. PMID:27004642

  2. Gait and motor imagery of gait in early schizophrenia.

    PubMed

    Lallart, Elise; Jouvent, Roland; Herrmann, François R; Beauchet, Olivier; Allali, Gilles

    2012-08-15

    Although gait disorders were described in schizophrenia, motor imagery of gait has not yet been studied in this pathology. We compared gait, motor imagery of gait and the difference between these two conditions in patients with schizophrenia and healthy age-matched controls. The mean ± standard deviation (S.D.) of Timed Up and Go (TUG), imagined TUG (iTUG) and delta time (i.e.; difference between TUG and iTUG), was used as outcomes. Covariables include Mini Mental State Examination, the Frontal Assessment Battery (FAB), FAB's subitems, the Positive and Negative Syndrome Scale and the Unified Parkinson's Disease Rating Scale (UPDRS). Seventeen patients with early schizophrenia and 15 healthy age-matched controls were assessed. Schizophrenia patients performed the TUG and the iTUG slower than the controls. Multivariate linear regressions showed that iTUG and delta time were associated with the conflicting instruction of the FAB. The present study provides the first evidence that patients with schizophrenia performed gait and motor imagery of gait slower than healthy controls. These deficits could be in part explained by impaired executive function and specifically by a disturbance in the sensitivity to interference. PMID:22445069

  3. Effects of non-weight bearing and hyperbaric oxygen therapy in vascular deprivation-induced osteonecrosis of the rat femoral head.

    PubMed

    Peskin, B; Shupak, A; Levin, D; Norman, D; Jacob, Z; Boss, J F; Misselevich, I; Reis, D N; Zinman, C

    2001-01-01

    We examined the role of hyperbaric oxygenation (HBO2) combined with non-weight bearing (NWB) in the treatment of vascular deprivation-induced osteonecrosis of the femoral head in the rat. Group 1 included 16 rats treated by a combination of NWB and HBO2. Twenty animals treated by NWB alone (group 2), and 18 rats which received no treatment (group 3), served as the control groups. Maximal benefit of HBO2 was observed on Day 30 of the study. The femoral heads were less deformed in group 1 animals (P = 0.07). Preservation of the femoral heads was observed in a larger proportion of the HBO2-treated animals (P = 0.06). A smaller proportion of high-grade new bone formation was observed, and more animals demonstrated well-regenerated hematopoietic tissue (P = 0.08). The tendency for less deformation of the femoral head in the HBO2-treated group might be a predictor of better function of the hipjoint. PMID:12153146

  4. Pedicle digital pad transfer and negative pressure wound therapy for reconstruction of the weight-bearing surface after complete digital loss in a dog.

    PubMed

    Or, M; Van Goethem, B; Polis, I; Spillebeen, A; Vandekerckhove, P; Saunders, J; de Rooster, H

    2015-01-01

    A young Labrador Retriever was presented for treatment of severe distal hindlimb necrosis caused by bandage ischemia. During digit amputation at the metatarsophalangeal joints, the third and fourth digital pads were salvaged and transferred to the metatarsal stump to create a weight-bearing surface. Negative pressure wound therapy (NPWT) was utilized for flap immobilization and to promote granulation tissue in the remaining wound defect. Sturdy adherence of the digital pads was achieved after only four days. The skin defect healed completely by second intention and the stump was epithelialized with a thin pad after three months. At the nine month follow-up examination, the stump had a thick hyperkeratinized pad. The dog walked and ran without any apparent signs of discomfort and compensated for the loss of limb length by extending the stifle and tarsocrural joints. Despite a challenging wound in a difficult anatomical location, digital pad flap transfer and NPWT proved successful in restoring long-term ambulation in an active large breed dog. PMID:25449188

  5. A pilot study of a plantar sensory evaluation system for early screening of diabetic neuropathy in a weight-bearing position.

    PubMed

    Ino, Shuichi; Chikai, Manabu; Takahashi, Noriyo; Ohnishi, Tadasuke; Doi, Kohki; Nunokawa, Kiyohiko

    2014-01-01

    The purpose of this study is to develop smart equipment to quantify plantar tactile sensibility for the early diagnosis and tracking of peripheral neuropathy caused by diabetes mellitus. In this paper, we offer a new testing system that is composed of a plantar tactile stimulation platform with a small moving contactor to stretch the skin tangentially, a response switch for each tactile stimulus, a motor control box, and a personal computer (PC) for psychophysical data processing. This quantitative sensory testing system has detailed measurements available and is easy to use compared with the conventional testing devices, such as von Frey monofilaments, pin-prick testing devices, and current perception threshold testers. When using our testing system in a weight-bearing position, we observed that the plantar tactile thresholds for the tangential stretching stimulus on the plantar surface of the foot ranged from approximately 10 um to 30 um for healthy subjects. However, the threshold for a subject with diabetes was nearly three times higher than that for healthy subjects. The significant difference between these values suggests that the plantar sensory evaluation system using the lateral skin stretch stimulation can be used for early diagnosis, for the accurate staging of diabetic neuropathy, and for evaluating its progression noninvasively in a clinic and at home. PMID:25570747

  6. Image-based compensation for involuntary motion in weight-bearing C-arm cone-beam CT scanning of knees

    NASA Astrophysics Data System (ADS)

    Unberath, Mathias; Choi, Jang-Hwan; Berger, Martin; Maier, Andreas; Fahrig, Rebecca

    2015-03-01

    We previously introduced four fiducial marker-based strategies to compensate for involuntary knee-joint motion during weight-bearing C-arm CT scanning of the lower body. 2D methods showed significant reduction of motion- related artifacts, but 3D methods worked best. However, previous methods led to increased examination times and patient discomfort caused by the marker attachment process. Moreover, sub-optimal marker placement may lead to decreased marker detectability and therefore unstable motion estimates. In order to reduce overall patient discomfort, we developed a new image-based 2D projection shifting method. A C-arm cone-beam CT system was used to acquire projection images of five healthy volunteers at various flexion angles. Projection matrices for the horizontal scanning trajectory were calibrated using the Siemens standard PDS-2 phantom. The initial reconstruction was forward projected using maximum-intensity projections (MIP), yielding an estimate of a static scan. This estimate was then used to obtain the 2D projection shifts via registration. For the scan with the most motion, the proposed method reproduced the marker-based results with a mean error of 2.90 mm +/- 1.43 mm (compared to a mean error of 4.10 mm +/- 3.03 mm in the uncorrected case). Bone contour surrounding modeling clay layer was improved. The proposed method is a first step towards automatic image-based, marker-free motion-compensation.

  7. 49 CFR 229.69 - Side bearings.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ....69 Side bearings. (a) Friction side bearings with springs designed to carry weight may not have more than 25 percent of the springs in any one nest broken. (b) Friction side bearings may not be run...

  8. 49 CFR 229.69 - Side bearings.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ....69 Side bearings. (a) Friction side bearings with springs designed to carry weight may not have more than 25 percent of the springs in any one nest broken. (b) Friction side bearings may not be run...

  9. Effect of load carriage on gait due to firefighting air bottle configuration.

    PubMed

    Park, Kiwon; Hur, Pilwon; Rosengren, Karl S; Horn, Gavin P; Hsiao-Wecksler, Elizabeth T

    2010-07-01

    The air bottle configuration (mass and size) used with a firefighter's self-contained breathing apparatus may affect functional gait performance and slip/trip/fall risk, contributing to one of the most common and costly fire ground injuries to this population. To examine the potential effect of bottle mass and size on firefighter gait performance, four 30-min air bottle configurations were tested. To quantify biomechanical gait performance, kinetic and kinematic gait data were collected on 24 male firefighters while walking at normal and fast speeds during three conditions (no obstacle, 10 cm or 30 cm stationary obstacle). Bottle mass, obstacle height and walking speed - but not bottle size - were found to significantly impact gait parameters. Ten subjects (42%) contacted the taller obstacle while wearing heavier bottles, suggesting greater risk for tripping. Heavier bottles also resulted in larger forces by the trailing leg in both the anterior-posterior and vertical directions, suggesting greater risk for slipping. These results suggest that increased bottle weight may result in a decrease in gait performance and an increase in fall risk. STATEMENT OF RELEVANCE: Occupations, such as firefighting, often require use of a self-contained breathing apparatus that includes a pressurised air bottle. No systematic assessment has investigated how modest changes in load carriage due to bottle configuration (mass and size) might affect gait behaviour, especially when crossing obstacles. Bottle mass, but not size, was found to decrease gait performance and increase fall risk. PMID:20582769

  10. Weight-Bearing MR Imaging as an Option in the Study of Gravitational Effects on the Vocal Tract of Untrained Subjects in Singing Phonation

    PubMed Central

    Traser, Louisa; Burdumy, Michael; Richter, Bernhard; Vicari, Marco; Echternach, Matthias

    2014-01-01

    Magnetic Resonance Imaging (MRI) of subjects in a supine position can be used to evaluate the configuration of the vocal tract during phonation. However, studies of speech phonation have shown that gravity can affect vocal tract shape and bias measurements. This is one of the reasons that MRI studies of singing phonation have used professionally trained singers as subjects, because they are generally considered to be less affected by the supine body position and environmental distractions. A study of untrained singers might not only contribute to the understanding of intuitive singing function and aid the evaluation of potential hazards for vocal health, but also provide insights into the effect of the supine position on singers in general. In the present study, an open configuration 0.25 T MRI system with a rotatable examination bed was used to study the effect of body position in 20 vocally untrained subjects. The subjects were asked to sing sustained tones in both supine and upright body positions on different pitches and in different register conditions. Morphometric measurements were taken from the acquired images of a sagittal slice depicting the vocal tract. The analysis concerning the vocal tract configuration in the two body positions revealed differences in 5 out of 10 measured articulatory parameters. In the upright position the jaw was less protruded, the uvula was elongated, the larynx more tilted and the tongue was positioned more to the front of the mouth than in the supine position. The findings presented are in agreement with several studies on gravitational effects in speech phonation, but contrast with the results of a previous study on professional singers of our group where only minor differences between upright and supine body posture were observed. The present study demonstrates that imaging of the vocal tract using weight-bearing MR imaging is a feasible tool for the study of sustained phonation in singing for vocally untrained subjects. PMID:25379885

  11. Effects of spaceflight on the murine mandible: Possible factors mediating skeletal changes in non-weight bearing bones of the head.

    PubMed

    Ghosh, Payal; Stabley, John N; Behnke, Bradley J; Allen, Matthew R; Delp, Michael D

    2016-02-01

    Spaceflight-induced remodeling of the skull is characterized by greater bone volume, mineral density, and mineral content. To further investigate the effects of spaceflight on other non-weight bearing bones of the head, as well as to gain insight into potential factors mediating the remodeling of the skull, the purpose of the present study was to determine the effects of spaceflight on mandibular bone properties. Female C57BL/6 mice were flown 15d on the STS-131 Space Shuttle mission (n=8) and 13d on the STS-135 mission (n=5) or remained as ground controls (GC). Upon landing, mandibles were collected and analyzed via micro-computed tomography for tissue mineralization, bone volume (BV/TV), and distance from the cemento-enamel junction to the alveolar crest (CEJ-AC). Mandibular mineralization was not different between spaceflight (SF) and GC mice for either the STS-131 or STS-135 missions. Mandibular BV/TV (combined cortical and trabecular bone) was lower in mandibles from SF mice on the STS-131 mission (80.7±0.8%) relative to that of GC (n=8) animals (84.2±1.2%), whereas BV/TV from STS-135 mice was not different from GC animals (n=7). The CEJ-AC distance was shorter in mandibles from STS-131 mice (0.217±0.004mm) compared to GC animals (0.283±0.009mm), indicating an anabolic (or anti-catabolic) effect of spaceflight, while CEJ-AC distance was similar between STS-135 and GC mice. These findings demonstrate that mandibular bones undergo skeletal changes during spaceflight and are susceptible to the effects of weightlessness. However, adaptation of the mandible to spaceflight is dissimilar to that of the cranium, at least in terms of changes in BV/TV. PMID:26545335

  12. A Global Gait Asymmetry Index.

    PubMed

    Cabral, Silvia; Resende, Renan A; Clansey, Adam C; Deluzio, Kevin J; Selbie, W Scott; Veloso, António P

    2016-04-01

    High levels of gait asymmetry are associated with many pathologies. Our long-term goal is to improve gait symmetry through real-time biofeedback of a symmetry index. Symmetry is often reported as a single metric or a collective signature of multiple discrete measures. While this is useful for assessment, incorporating multiple feedback metrics presents too much information for most subjects to use as visual feedback for gait retraining. The aim of this article was to develop a global gait asymmetry (GGA) score that could be used as a biofeedback metric for gait retraining and to test the effectiveness of the GGA for classifying artificially-induced asymmetry. Eighteen participants (11 males; age 26.9 y [SD = 7.7]; height 1.8 m [SD = 0.1]; body mass 72.7 kg [SD = 8.9]) walked on a treadmill in 3 symmetry conditions, induced by wearing custom-made sandals: a symmetric condition (identical sandals) and 2 asymmetric conditions (different sandals). The GGA score was calculated, based on several joint angles, and compared between conditions. Significant differences were found among all conditions (P < .001), meaning that the GGA score is sensitive to different levels of asymmetry, and may be useful for rehabilitation and assessment. PMID:26502455

  13. Gait analysis in forensic medicine

    NASA Astrophysics Data System (ADS)

    Larsen, Peter K.; Simonsen, Erik B.; Lynnerup, Niels

    2007-01-01

    We have combined the basic human ability to recognize other individuals with functional anatomical and biomechanical knowledge, in order to analyze the gait of perpetrators as recorded on surveillance video. The perpetrators are then compared with similar analyses of suspects. At present we give a statement to the police as to whether the perpetrator has a characteristic gait pattern compared to normal gait, and if a suspect has a comparable gait pattern. We have found agreements such as: limping, varus instability in the knee at heel strike, larger lateral flexion of the spinal column to one side than the other, inverted ankle during stance, pronounced sagittal head-movements, and marked head-shoulder posture. Based on these characteristic features, we state whether suspect and perpetrator could have the same identity but it is not possible to positively identify the perpetrator. Nevertheless, we have been involved in several cases where the court has found that this type of gait analysis, especially combined with photogrammetry, was a valuable tool. The primary requisites are surveillance cameras recording with sufficient frequency, ideally about 15 Hz, which are positioned in frontal and preferably also in profile view.

  14. Bearing system

    DOEpatents

    Kapich, Davorin D.

    1987-01-01

    A bearing system includes backup bearings for supporting a rotating shaft upon failure of primary bearings. In the preferred embodiment, the backup bearings are rolling element bearings having their rolling elements disposed out of contact with their associated respective inner races during normal functioning of the primary bearings. Displacement detection sensors are provided for detecting displacement of the shaft upon failure of the primary bearings. Upon detection of the failure of the primary bearings, the rolling elements and inner races of the backup bearings are brought into mutual contact by axial displacement of the shaft.

  15. Safety concept for robotic gait trainers.

    PubMed

    Schmidt, H; Hesse, S; Bernhardt, R

    2004-01-01

    The work presents a newly developed safety concept for application of robotic walking simulators based on the principle of programmable footplates in gait rehabilitation. Unlike robotic hand devices or exoskeleton robots for gait training on treadmills, which can be built relatively lightweight and require only small drives which can hardly do harm to the patient, a programmable footplate walking simulator with permanent foot fixture essentially needs to have powerful drives in order to carry and move the full body weight of the patient. The developed safety concept comprises several redundant algorithms and devices in the real-time robot control software, electrical emergency stop circuitry and machine mechanics. The mechanical core is a machine design offering maximum passive security by covering all moving parts (i.e. robot drives and linkages) and a newly developed foot safety release binding, which is mounted on each footplate. The release binding allows a safe release from the footplate in all directions in any degree of freedom in the sagittal plane. It is combined with an ankle goniometer which is equipped with adjustable emergency stop limit switches, thus ensuring that the allowed ankle range-of-motion is not exceeded. PMID:17270834

  16. A mechanical energy analysis of gait initiation

    NASA Technical Reports Server (NTRS)

    Miller, C. A.; Verstraete, M. C.

    1999-01-01

    The analysis of gait initiation (the transient state between standing and walking) is an important diagnostic tool to study pathologic gait and to evaluate prosthetic devices. While past studies have quantified mechanical energy of the body during steady-state gait, to date no one has computed the mechanical energy of the body during gait initiation. In this study, gait initiation in seven normal male subjects was studied using a mechanical energy analysis to compute total body energy. The data showed three separate states: quiet standing, gait initiation, and steady-state gait. During gait initiation, the trends in the energy data for the individual segments were similar to those seen during steady-state gait (and in Winter DA, Quanbury AO, Reimer GD. Analysis of instantaneous energy of normal gait. J Biochem 1976;9:253-257), but diminished in amplitude. However, these amplitudes increased to those seen in steady-state during the gait initiation event (GIE), with the greatest increase occurring in the second step due to the push-off of the foundation leg. The baseline level of mechanical energy was due to the potential energy of the individual segments, while the cyclic nature of the data was indicative of the kinetic energy of the particular leg in swing phase during that step. The data presented showed differences in energy trends during gait initiation from those of steady state, thereby demonstrating the importance of this event in the study of locomotion.

  17. Gait Stability in Children with Cerebral Palsy

    ERIC Educational Resources Information Center

    Bruijn, Sjoerd M.; Millard, Matthew; van Gestel, Leen; Meyns, Pieter; Jonkers, Ilse; Desloovere, Kaat

    2013-01-01

    Children with unilateral Cerebral Palsy (CP) have several gait impairments, amongst which impaired gait stability may be one. We tested whether a newly developed stability measure (the foot placement estimator, FPE) which does not require long data series, can be used to asses gait stability in typically developing (TD) children as well as…

  18. Gait Stability in Children with Cerebral Palsy

    ERIC Educational Resources Information Center

    Bruijn, Sjoerd M.; Millard, Matthew; van Gestel, Leen; Meyns, Pieter; Jonkers, Ilse; Desloovere, Kaat

    2013-01-01

    Children with unilateral Cerebral Palsy (CP) have several gait impairments, amongst which impaired gait stability may be one. We tested whether a newly developed stability measure (the foot placement estimator, FPE) which does not require long data series, can be used to asses gait stability in typically developing (TD) children as well as

  19. Motor imagery of gait tasks in individuals with Parkinson disease.

    PubMed

    Pickett, Kristen A; Peterson, Daniel S; Earhart, Gammon M

    2012-01-01

    We developed a questionnaire to assess motor imagery (MI) of gait and administered it to 33 controls and 28 individuals with PD. Our goals were: 1) compare gait MI in individuals with and without PD, 2) determine whether walking performance relates to gait MI and 3) compare gait MI in individuals with PD with and without freezing of gait. Gait MI was not different between PD and controls. There was no correlation between walking performance and gait MI, and no difference in gait MI between freezers and nonfreezers. The gait imagery questionnaire may be useful for imaging studies involving imagined gait. PMID:23939404

  20. Gait-Based Person Identification Robust to Changes in Appearance

    PubMed Central

    Iwashita, Yumi; Uchino, Koji; Kurazume, Ryo

    2013-01-01

    The identification of a person from gait images is generally sensitive to appearance changes, such as variations of clothes and belongings. One possibility to deal with this problem is to collect possible subjects' appearance changes in a database. However, it is almost impossible to predict all appearance changes in advance. In this paper, we propose a novel method, which allows robustly identifying people in spite of changes in appearance, without using a database of predicted appearance changes. In the proposed method, firstly, the human body image is divided into multiple areas, and features for each area are extracted. Next, a matching weight for each area is estimated based on the similarity between the extracted features and those in the database for standard clothes. Finally, the subject is identified by weighted integration of similarities in all areas. Experiments using the gait database CASIA show the best correct classification rate compared with conventional methods experiments. PMID:23783739

  1. Effects of Design Variants in Lower-Limb Prostheses on Gait Synergy

    PubMed Central

    Pitkin, Mark R.

    2016-01-01

    A lower-limb prosthesis is the mechanical device with which an amputee’s residual limb interacts with the walking surface. The pressure and shear forces that affect the residuum due to prosthesis use are the sources of pain, residual-limb skin problems and gait deviations. Direct approaches to reducing these problems include improving fit, alignment technique and socket design as well as increasing cushioning with socket liners. A summary of typical malalignments and their consequences is presented. The malalignments are considered sources of excessive moments applied to the residuum, which simplifies the analysis of a patient’s gait. A better design of prosthetic joints could improve prosthetic gait. This article addresses the key mechanical parameter of prosthetic joints, namely the dependence “moment of resistance/angle of deflection.” A mathematical model has been developed that links stresses on the residuum in transtibial amputees with the moment of resistance in the prosthetic ankle at the critical gait phases. Analysis of the model yields a substantial decrease in stresses on the residuum during the most demanding, load-bearing phase of stance if the moment of resistance in the ankle is similar to that seen in the biological ankle joint. Gait study shows use of the experimental rolling-joint prosthetic foot more closely simulates normal gait synergy than the SACH foot.

  2. Association between bone stiffness and nutritional biomarkers combined with weight-bearing exercise, physical activity, and sedentary time in preadolescent children. A case-control study.

    PubMed

    Herrmann, Diana; Pohlabeln, Hermann; Gianfagna, Francesco; Konstabel, Kenn; Lissner, Lauren; Mårild, Staffan; Molnar, Dénes; Moreno, Luis A; Siani, Alfonso; Sioen, Isabelle; Veidebaum, Toomas; Ahrens, Wolfgang

    2015-09-01

    Physical activity (PA) and micronutrients such as calcium (Ca), vitamin D (25OHD), and phosphate (PO) are important determinants of skeletal development. This case-control study examined the association of these nutritional biomarkers and different PA behaviours, such as habitual PA, weight-bearing exercise (WBE) and sedentary time (SED) with bone stiffness (SI) in 1819 2-9-year-old children from the IDEFICS study (2007-2008). SI was measured on the calcaneus using quantitative ultrasound. Serum and urine Ca and PO and serum 25OHD were determined. Children's sports activities were reported by parents using a standardised questionnaire. A subsample of 1089 children had accelerometer-based PA data (counts per minute, cpm). Moderate-to-vigorous PA (MVPA) and SED were estimated. Children with poor SI (below the 15th age-/sex-/height-specific percentile) were defined as cases (N=603). Randomly selected controls (N=1216) were matched by age, sex, and country. Odds ratios (OR) for poor SI were calculated by conditional logistic regression for all biomarkers and PA behaviour variables separately and combined (expressed as tertiles and dichotomised variables, respectively). ORs were adjusted for fat-free mass, dairy product consumption, and daylight duration. We observed increased ORs for no sports (OR=1.39, p<0.05), PA levels below 524 cpm (OR=1.85, p<0.05) and MVPA below 4.2% a day (OR=1.69, p<0.05) compared to WBE, high PA levels (<688 cpm) and high MVPA (6.7%), respectively. SED was not associated with SI. ORs were moderately elevated for low serum Ca and 25OHD. However, biomarkers were not statistically significantly associated with SI and did not modify the association between PA behaviours and SI. Although nutritional biomarkers appear to play a minor role compared to the osteogenic effect of PA and WBE, it is noteworthy that the highest risk for poor SI was observed for no sports or low MVPA combined with lower serum Ca (<2.5 mmol/l) or lower 25OHD (<43.0 nmol/l). PMID:25952968

  3. Characteristics of metal and ceramic total hip bearing surfaces and their effect on long-term ultra high molecular weight polyethylene wear.

    PubMed

    Davidson, J A

    1993-09-01

    The micromechanics of ultra high molecular weight polyethylene (UHMWPE) wear in total hip replacement are very complex. Polyethylene wear from the metal head and debris formation are two common types of wear. There are additional wear-related processes occurring at the metal-bearing surfaces that are not well-known, however. This study outlines these processes, including (1) surface wettability changes, (2) oxidative wear of metal surfaces, (3) microabrasion of metal surfaces from oxide film damage, and (4) surface abrasion from three-body polymethylmethacrylate and bone debris. These processes can contribute to metal ion release and a gradual increase in the roughness of the metal surfaces. This can lead to increased long-term UHMWPE wear. Of the metal alloys currently used in total hip replacements, Co-Cr-Mo alloy is significantly more resistant to roughening processes. Hard, stable, oxide: ceramic surfaces articulating against UHMWPE are essentially immune to these surface-roughening processes, however. In addition, they provide a more wettable surface, further minimizing polyethylene wear relative to metal surfaces. By analyzing metal release rates from metal-polyethylene wear tests, it is shown here that Co-Cr-Mo is gradually removed at a rate of about 0.1 micron per year (10(6) cycles), whereas 316L stainless steel is removed on the order of 0.2 microns per year and Ti-6Al-4V on the order of 1 micron per year. The wear rate of Co-Cr-Mo articulating against itself is reported to be still greater, at about 2-4 microns per year after an initial wear-in period. Because metal is gradually removed with articulation time, surface-hardening methods such as nitrogen ion implantation can be expected to provide only temporary resistance to these metal removal and surface-roughening processes. Hard, stable ceramic surfaces such as Al2O3 and ZrO2, however, can be expected to maintain their initial surface finish and thus minimize UHMWPE wear in the long term. PMID:8358943

  4. Recent advances in functional neuroimaging of gait.

    PubMed

    Bakker, M; Verstappen, C C P; Bloem, B R; Toni, I

    2007-01-01

    In this review, we discuss the contribution of functional neuroimaging to the understanding of the cerebral control of gait in humans, both in healthy subjects and in patients with Parkinson's disease. We illustrate different approaches that have been used to address this issue, ranging from the imaging of actual gait performance to the study of initiation and imagery of gait. We also consider related approaches focused on specific aspects of gait, like those addressed by repetitive foot movements. We provide a critical discussion of advantages and disadvantages of each approach, emphasizing crucial issues to be addressed for a better understanding of the neural control of human gait. PMID:17622483

  5. Gait characterization for osteoarthritis patients using wearable gait sensors (H-Gait systems).

    PubMed

    Tadano, Shigeru; Takeda, Ryo; Sasaki, Keita; Fujisawa, Tadashi; Tohyama, Harukazu

    2016-03-21

    The objective of this work was to investigate the possibilities of using the wearable sensors-based H-Gait system in an actual clinical trial and proposes new gait parameters for characterizing OA gait. Seven H-Gait sensors, consisting of tri-axial inertial sensors, were attached to seven lower limb body segments (pelvis, both thighs, both shanks and both feet). The acceleration and angular velocity data measured were used to estimate three-dimensional kinematic parameters of patients during level walking. Three new parameters were proposed to assess the severity of OA based on the characteristics of these joint center trajectories in addition to conventional gait spatio-temporal parameters. The experiment was conducted on ten subjects with knee OA. The kinematic results obtained (hip, knee and ankle joint angles, joint trajectory in the horizontal and sagittal planes) were compared with those from a reference healthy (control) group. As a result, the angle between the right and left knee trajectories along with that of the ankle joint trajectories were almost twice as large (21.3° vs. 11.6° and 14.9° vs. 7.8°) compared to those of the healthy subjects. In conclusion, it was found that the ankle joints during stance abduct less to avoid adduction at the knee as the severity of OA increases and lead to more acute angles (less parallel) between the right and left knee/ankle joints in the horizontal plane. This method was capable to provide quantitative information about the gait of OA patients and has the advantage to allow for out-of-laboratory monitoring. PMID:26947036

  6. Arthrodesis of the first metatarsal-phalangeal joint with flexible, ridged titanium intramedullary nails alone or supplemented with static staples and immediate weight bearing: a consecutive series of 148 procedures.

    PubMed

    Roukis, Thomas S; Meusnier, Tristan; Augoyard, Marc

    2012-02-01

    Myriad forms of fixation have been proposed for arthrodesis of the first metatarsal-phalangeal joint (MTPJ). However, nonunion of the arthrodesis site remains a common complication. The authors performed a retrospective review of all patients undergoing arthrodesis of the first MTPJ with flexible titanium intramedullary nails alone or supplemented with static staples followed by immediate protected weight bearing. Subjects were included if they had surgery performed only by one of us; not undergone bilateral surgery in the same setting; surgery for pathology of the first MTPJ other than rheumatoid arthritis; weight-bearing preoperative radiographs; postoperative weight-bearing radiographs demonstrating presence or absence of union at the arthrodesis site; initiated weight bearing on the operative foot immediately postoperative in a protective shoe; and documentation of any complications. A total of 128 patients (148 feet) met inclusion criteria and were included. There were 110 (85.9%) females and 18 (14.1%) males with a mean age ± SD of 64 ± 14.1 years. Indications included (a) 93 (62.8%) severe hallux valgus deformity, (b) 37 (25%) hallux rigidus, and (c) 18 (12.2%) failed first MTPJ surgeries. Ten different configurations where included based on the requirements needed to achieve a solid construct intraoperatively. There were a total of 9 (6.1%) complications consisting of 4 (2.7%) asymptomatic nonunions, 4 (2.7%) hardware removals, and 1 (0.7%) loss of reduction requiring revision surgery. The incidence of nonunion with flexible titanium intramedullary nails alone or supplemented with static staples followed by immediate protected weight bearing for predominantly severe hallux valgus and hallux rigidus is lower than the historic mean for most other fixation techniques. However, there is still a need for methodologically sound prospective cohort studies that focus on the use of isolated arthrodesis of the first MTPJ for purely severe hallux valgus or hallux rigidus, and comparison of the technique presented here with other modern osteosynthesis techniques. Levels of Evidence : Therapeutic, Level IV. PMID:22134438

  7. Bear Scratch

    When looking for a place to set up a trapping location, scientists look for existing bear sign such as scratches on trees and bear scat. Sometimes traps are set in areas that have no obvious bear sign to determine if indeed bears are present....

  8. Footwear and Foam Surface Alter Gait Initiation of Typical Subjects

    PubMed Central

    Vieira, Marcus Fraga; Sacco, Isabel de Camargo Neves; Nora, Fernanda Grazielle da Silva Azevedo; Rosenbaum, Dieter; Lobo da Costa, Paula Hentschel

    2015-01-01

    Gait initiation is the task commonly used to investigate the anticipatory postural adjustments necessary to begin a new gait cycle from the standing position. In this study, we analyzed whether and how foot-floor interface characteristics influence the gait initiation process. For this purpose, 25 undergraduate students were evaluated while performing a gait initiation task in three experimental conditions: barefoot on a hard surface (barefoot condition), barefoot on a soft surface (foam condition), and shod on a hard surface (shod condition). Two force plates were used to acquire ground reaction forces and moments for each foot separately. A statistical parametric mapping (SPM) analysis was performed in COP time series. We compared the anterior-posterior (AP) and medial-lateral (ML) resultant center of pressure (COP) paths and average velocities, the force peaks under the right and left foot, and the COP integral x force impulse for three different phases: the anticipatory postural adjustment (APA) phase (Phase 1), the swing-foot unloading phase (Phase 2), and the support-foot unloading phase (Phase 3). In Phase 1, significantly smaller ML COP paths and velocities were found for the shod condition compared to the barefoot and foam conditions. Significantly smaller ML COP paths were also found in Phase 2 for the shod condition compared to the barefoot and foam conditions. In Phase 3, increased AP COP velocities were found for the shod condition compared to the barefoot and foam conditions. SPM analysis revealed significant differences for vector COP time series in the shod condition compared to the barefoot and foam conditions. The foam condition limited the impulse-generating capacity of COP shift and produced smaller ML force peaks, resulting in limitations to body-weight transfer from the swing to the support foot. The results suggest that footwear and a soft surface affect COP and impose certain features of gait initiation, especially in the ML direction of Phase 1. PMID:26270323

  9. Genetic feature selection for gait recognition

    NASA Astrophysics Data System (ADS)

    Tafazzoli, Faezeh; Bebis, George; Louis, Sushil; Hussain, Muhammad

    2015-01-01

    Many research studies have demonstrated that gait can serve as a useful biometric modality for human identification at a distance. Traditional gait recognition systems, however, have mostly been evaluated without explicitly considering the most relevant gait features, which might have compromised performance. We investigate the problem of selecting a subset of the most relevant gait features for improving gait recognition performance. This is achieved by discarding redundant and irrelevant gait features while preserving the most informative ones. Motivated by our previous work on feature subset selection using genetic algorithms (GAs), we propose using GAs to select an optimal subset of gait features. First, features are extracted using kernel principal component analysis (KPCA) on spatiotemporal projections of gait silhouettes. Then, GA is applied to select a subset of eigenvectors in KPCA space that best represents a subject's identity. Each gait pattern is then represented by projecting it only on the eigenvectors selected by the GA. To evaluate the effectiveness of the selected features, we have experimented with two different classifiers: k nearest-neighbor and Naïve Bayes classifier. We report considerable gait recognition performance improvements on the Georgia Tech and CASIA databases.

  10. 49 CFR 229.69 - Side bearings.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Side bearings. 229.69 Section 229.69....69 Side bearings. (a) Friction side bearings with springs designed to carry weight may not have more than 25 percent of the springs in any one nest broken. (b) Friction side bearings may not be run...

  11. 49 CFR 229.69 - Side bearings.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Side bearings. 229.69 Section 229.69....69 Side bearings. (a) Friction side bearings with springs designed to carry weight may not have more than 25 percent of the springs in any one nest broken. (b) Friction side bearings may not be run...

  12. 49 CFR 229.69 - Side bearings.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Side bearings. 229.69 Section 229.69....69 Side bearings. (a) Friction side bearings with springs designed to carry weight may not have more than 25 percent of the springs in any one nest broken. (b) Friction side bearings may not be run...

  13. Cerebral Palsy Gait, Clinical Importance

    PubMed Central

    TUGUI, Raluca Dana; ANTONESCU, Dinu

    2013-01-01

    ABSTRACT Cerebral palsy refers to a lesion on an immature brain, that determines permanent neurological disorders. Knowing the exact cause of the disease does not alter the treatment management. The etiology is 2-2.5/1000 births and the rate is constant in the last 40-50 years because advances in medical technologies have permitted the survival of smaller and premature new born children. Gait analysis has four directions: kinematics (represents body movements analysis without calculating the forces), kinetics (represents body moments and forces), energy consumption (measured by oximetry), and neuromuscular activity (measured by EMG). Gait analysis can observe specific deviations in a patient, allowing us to be more accurate in motor diagnoses and treatment solutions: surgery intervention, botulinum toxin injection, use of orthosis, physical kinetic therapy, oral medications, baclofen pump. PMID:24790675

  14. Gait Analysis in Cervical Spondylotic Myelopathy

    PubMed Central

    Endo, Kenji; Suzuki, Hidekazu; Tanaka, Hidetoshi; Shishido, Takaaki; Yamamoto, Kengo

    2015-01-01

    Study Design Gait analysis of patients with cervical spondylotic myelopathy (CSM) by using a sheet-type gait analysis system. Purpose The aim of this study was to compare the gait patterns of patients with CSM, evaluated by the Nurick grades, and to determine the threshold values of gait parameters predicting the occurrence of a fall by using a gait recorder. Overview of Literature Gait disorder due to CSM may progress to severe paraplegia, following even a minor trauma such as a fall. The indications for the surgery of CSM without severe paralysis remain controversial. The quantitative gait analysis and the decision for decompressive surgery in patients with CSM are important in order to prevent severe paraplegia from a fall. Methods One hundred thirty-two subjects (normal, 34; CSM, 98) underwent gait analysis by using a sensor sheet. Measurements of gait cycle parameters included the step and stride length, step width, foot angle, swing phase, and stance phase. CSM was assessed by Nurick grade. Results Although the clinical symptoms were lacking, Nurick grade 1 had significant abnormalities in the parameters of velocity, step length, and step angle (p<0.05). Regarding the Nurick grade and walking phase, the length of the stance phase was increased to more than 70% of the entire walking cycle in Nurick grade 4. Conclusions Gait analysis was an objective tool for evaluating the gait stability. Our results suggested that when the percentage of the stance phase in the gait cycle increases to above 70%, the CSM patients have an increased fall risk. PMID:26097646

  15. Abnormal gait sequence in locomotion after atropine treatment of catecholamine-deficient akinetic rats.

    PubMed Central

    Pellis, S M; Pellis, V C; Chesire, R M; Rowland, N; Teitelbaum, P

    1987-01-01

    Excessive, abnormal locomotion occurs after a high dose (25-50 mg/kg) of atropine sulfate to rats already akinetic due to catecholamine deficiency from intraventricular administration of 6-hydroxydopamine. This abnormal locomotion involves an abnormal gait sequence [right (R) hindleg (H), left (L) foreleg (F), LH, RF] instead of the normal gait sequence (RH, RF, LH, LF). In such animals atropine progressively (i) decreases hindleg step size, (ii) decreases arching of the trunk, and (iii) increases foreleg step size. These factors combine to change the ratio of front/hind body support. If the body stretches too far and the hindleg step is too small, a given hindleg step supports insufficient weight to remove weight from the ipsilateral foreleg; consequently, the opposite foreleg must execute the next step, producing the abnormal gait sequence. Thus, atropine affects gait sequence indirectly; it acts on at least three variables that affect how body weight is distributed and shifted during locomotion. To maintain stability during such locomotion, gait sequence is appropriately altered. PMID:3120199

  16. Identification of humans using gait.

    PubMed

    Kale, Amit; Sundaresan, Aravind; Rajagopalan, A N; Cuntoor, Naresh P; Roy-Chowdhury, Amit K; Krüger, Volker; Chellappa, Rama

    2004-09-01

    We propose a view-based approach to recognize humans from their gait. Two different image features have been considered: the width of the outer contour of the binarized silhouette of the walking person and the entire binary silhouette itself. To obtain the observation vector from the image features, we employ two different methods. In the first method, referred to as the indirect approach, the high-dimensional image feature is transformed to a lower dimensional space by generating what we call the frame to exemplar (FED) distance. The FED vector captures both structural and dynamic traits of each individual. For compact and effective gait representation and recognition, the gait information in the FED vector sequences is captured in a hidden Markov model (HMM). In the second method, referred to as the direct approach, we work with the feature vector directly (as opposed to computing the FED) and train an HMM. We estimate the HMM parameters (specifically the observation probability B) based on the distance between the exemplars and the image features. In this way, we avoid learning high-dimensional probability density functions. The statistical nature of the HMM lends overall robustness to representation and recognition. The performance of the methods is illustrated using several databases. PMID:15449579

  17. Increased treatment durations lead to greater improvements in non-weight bearing dorsiflexion range of motion for asymptomatic individuals immediately following an anteroposterior grade IV mobilisation of the talus.

    PubMed

    Holland, Christopher James; Campbell, Kevin; Hutt, Kim

    2015-08-01

    Manual therapy aims to minimise pain and restore joint mobility and function. Joint mobilisations are integral to these techniques, with anteroposterior (AP) talocrural joint mobilisations purported to increase dorsiflexion range of motion (DF-ROM). This study aimed to determine whether different treatment durations of single grade IV anteroposterior talocrural joint mobilisations elicit statistically significant differences in DF-ROM. Sixteen asymptomatic male football players (age = 27.1 ± 5.3 years) participated in the study. Non-weight bearing (NWB) and weight bearing (WB) DF-ROM was measured before and after 4 randomised treatment conditions: control treatment, 30 s, 1 min, 2 min. NWB DF-ROM was measured using a universal goniometer, and WB DF-ROM using the weight-bearing lunge test. A within-subjects design was employed so that all participants received each of the treatment conditions. A 4 × 4 balanced Latin square design and 1 week interval between sessions reduced any residual effects. Two-way repeated measures ANOVA revealed a significant improvement in DF-ROM following all AP mobilisation treatments (p < 0.001). The within subjects contrasts showed that increases in treatment duration was associated with statistically significant improvements in DF-ROM (NWB DF-ROM control = 0.01%, 30 s = 14.2%, 1 min = 21.6%, 2 min = 32.8%; WB DF-ROM control = 0.01%, 30 s = 5.0%, 1 min = 7.6%, 2 min = 10.9%; p < 0.05). However, WB DF-ROM improvements were below the minimal detectable change scores needed to conclude that improvements were not a consequence of measurement error. This research shows that single session mobilisations can elicit NWB DF-ROM improvements in asymptomatic individuals in the absence of pain, whilst increases in treatment duration confer greater improvements in NWB DF-ROM within this population. PMID:25765456

  18. Optics in gait analysis and anthropometry

    NASA Astrophysics Data System (ADS)

    Silva Moreno, Alejandra Alicia

    2013-11-01

    Since antiquity, human gait has been studied to understand human movement, the kind of gait, in some cases, can cause musculoskeletal disorders or other health problems; in addition, also from antiquity, anthropometry has been important for the design of human items such as workspaces, tools, garments, among others. Nowadays, thanks to the development of optics and electronics, more accurate studies of gait and anthropometry can be developed. This work will describe the most important parameters for gait analysis, anthropometry and the optical systems used.

  19. Mixed gaits in small avian terrestrial locomotion.

    PubMed

    Andrada, Emanuel; Haase, Daniel; Sutedja, Yefta; Nyakatura, John A; Kilbourne, Brandon M; Denzler, Joachim; Fischer, Martin S; Blickhan, Reinhard

    2015-01-01

    Scientists have historically categorized gaits discretely (e.g. regular gaits such as walking, running). However, previous results suggest that animals such as birds might mix or regularly or stochastically switch between gaits while maintaining a steady locomotor speed. Here, we combined a novel and completely automated large-scale study (over one million frames) on motions of the center of mass in several bird species (quail, oystercatcher, northern lapwing, pigeon, and avocet) with numerical simulations. The birds studied do not strictly prefer walking mechanics at lower speeds or running mechanics at higher speeds. Moreover, our results clearly display that the birds in our study employ mixed gaits (such as one step walking followed by one step using running mechanics) more often than walking and, surprisingly, maybe as often as grounded running. Using a bio-inspired model based on parameters obtained from real quails, we found two types of stable mixed gaits. In the first, both legs exhibit different gait mechanics, whereas in the second, legs gradually alternate from one gait mechanics into the other. Interestingly, mixed gaits parameters mostly overlap those of grounded running. Thus, perturbations or changes in the state induce a switch from grounded running to mixed gaits or vice versa. PMID:26333477

  20. Mixed gaits in small avian terrestrial locomotion

    PubMed Central

    Andrada, Emanuel; Haase, Daniel; Sutedja, Yefta; Nyakatura, John A.; M. Kilbourne, Brandon; Denzler, Joachim; Fischer, Martin S.; Blickhan, Reinhard

    2015-01-01

    Scientists have historically categorized gaits discretely (e.g. regular gaits such as walking, running). However, previous results suggest that animals such as birds might mix or regularly or stochastically switch between gaits while maintaining a steady locomotor speed. Here, we combined a novel and completely automated large-scale study (over one million frames) on motions of the center of mass in several bird species (quail, oystercatcher, northern lapwing, pigeon, and avocet) with numerical simulations. The birds studied do not strictly prefer walking mechanics at lower speeds or running mechanics at higher speeds. Moreover, our results clearly display that the birds in our study employ mixed gaits (such as one step walking followed by one step using running mechanics) more often than walking and, surprisingly, maybe as often as grounded running. Using a bio-inspired model based on parameters obtained from real quails, we found two types of stable mixed gaits. In the first, both legs exhibit different gait mechanics, whereas in the second, legs gradually alternate from one gait mechanics into the other. Interestingly, mixed gaits parameters mostly overlap those of grounded running. Thus, perturbations or changes in the state induce a switch from grounded running to mixed gaits or vice versa. PMID:26333477

  1. Gait-related cerebral alterations in patients with Parkinson's disease with freezing of gait.

    PubMed

    Snijders, Anke H; Leunissen, Inge; Bakker, Maaike; Overeem, Sebastiaan; Helmich, Rick C; Bloem, Bastiaan R; Toni, Ivan

    2011-01-01

    Freezing of gait is a common, debilitating feature of Parkinson's disease. We have studied gait planning in patients with freezing of gait, using motor imagery of walking in combination with functional magnetic resonance imaging. This approach exploits the large neural overlap that exists between planning and imagining a movement. In addition, it avoids confounds introduced by brain responses to altered motor performance and somatosensory feedback during actual freezing episodes. We included 24 patients with Parkinson's disease: 12 patients with freezing of gait, 12 matched patients without freezing of gait and 21 matched healthy controls. Subjects performed two previously validated tasks--motor imagery of gait and a visual imagery control task. During functional magnetic resonance imaging scanning, we quantified imagery performance by measuring the time required to imagine walking on paths of different widths and lengths. In addition, we used voxel-based morphometry to test whether between-group differences in imagery-related activity were related to structural differences. Imagery times indicated that patients with freezing of gait, patients without freezing of gait and controls engaged in motor imagery of gait, with matched task performance. During motor imagery of gait, patients with freezing of gait showed more activity than patients without freezing of gait in the mesencephalic locomotor region. Patients with freezing of gait also tended to have decreased responses in mesial frontal and posterior parietal regions. Furthermore, patients with freezing of gait had grey matter atrophy in a small portion of the mesencephalic locomotor region. The gait-related hyperactivity of the mesencephalic locomotor region correlated with clinical parameters (freezing of gait severity and disease duration), but not with the degree of atrophy. These results indicate that patients with Parkinson's disease with freezing of gait have structural and functional alterations in the mesencephalic locomotor region. We suggest that freezing of gait might emerge when altered cortical control of gait is combined with a limited ability of the mesencephalic locomotor region to react to that alteration. These limitations might become particularly evident during challenging events that require precise regulation of step length and gait timing, such as turning or initiating walking, which are known triggers for freezing of gait. PMID:21126990

  2. The Latest Lessons Learned from Retrieval Analyses of Ultra-High Molecular Weight Polyethylene, Metal-on-Metal, and Alternative Bearing Total Disc Replacements

    PubMed Central

    Kurtz, Steven M.; Toth, Jeffrey M.; Siskey, Ryan; Ciccarelli, Lauren; MacDonald, Dan; Isaza, Jorge; Lanman, Todd; Punt, Ilona; Steinbeck, Marla; Goffin, Jan; van Ooij, André

    2012-01-01

    Knowledge regarding the in vivo performance and periposthetic tissue response of cervical and lumbar total disc replacements (TDRs) continues to expand. This review addresses the following four main questions: 1) What are the latest lessons learned from polyethylene in large joints and how are they relevant to current TDRs? 2) What are the latest lessons learned regarding adverse local tissue reactions from metal-on-metal, CoCr bearings in large joints and how are they relevant to current TDRs? 3) What advancements have been made in understanding the in vivo performance of alternative biomaterials, such as stainless steel and polycarbonate urethane, for TDRs in the past five years? 4) How has retrieval analysis of all these various artificial disc bearing technologies advanced the state of the art in preclinical testing of TDRs? The study of explanted artificial discs and their associated tissues can help inform bearing selection as well as the design of future generations of disc arthroplasty. Analyzing retrieved artificial discs is also essential for validating preclinical test methods. PMID:22904606

  3. Gear bearings

    NASA Technical Reports Server (NTRS)

    Vranish, John M. (Inventor)

    2003-01-01

    A gear bearing having a first gear and a second gear, each having a plurality of teeth. Each gear operates on two non-parallel surfaces of the opposing gear teeth to perform both gear and bearing functions simultaneously. The gears are moving at substantially the same speed at their contact points. The gears may be roller gear bearings or phase-shifted gear bearings, and may be arranged in a planet/sun system or used as a transmission.

  4. Single-trial classification of gait and point movement preparation from human EEG.

    PubMed

    Velu, Priya D; de Sa, Virginia R

    2013-01-01

    Neuroimaging studies provide evidence of cortical involvement immediately before and during gait and during gait-related behaviors such as stepping in place or motor imagery of gait. Here we attempt to perform single-trial classification of gait intent from another movement plan (point intent) or from standing in place. Subjects walked naturally from a starting position to a designated ending position, pointed at a designated position from the starting position, or remained standing at the starting position. The 700 ms of recorded electroencephalography (EEG) before movement onset was used for single-trial classification of trials based on action type and direction (left walk, forward walk, right walk, left point, right point, and stand) as well as action type regardless of direction (stand, walk, point). Classification using regularized LDA was performed on a principal components analysis (PCA) reduced feature space composed of coefficients from levels 1 to 9 of a discrete wavelet decomposition using the Daubechies 4 wavelet. We achieved significant classification for all conditions, with errors as low as 17% when averaged across nine subjects. LDA and PCA highly weighted frequency ranges that included movement related potentials (MRPs), with smaller contributions from frequency ranges that included mu and beta idle motor rhythms. Additionally, error patterns suggested a spatial structure to the EEG signal. Future applications of the cortical gait intent signal may include an additional dimension of control for prosthetics, preemptive corrective feedback for gait disturbances, or human computer interfaces (HCI). PMID:23781166

  5. Residual Elimination Algorithm Enhancements to Improve Foot Motion Tracking During Forward Dynamic Simulations of Gait.

    PubMed

    Jackson, Jennifer N; Hass, Chris J; Fregly, Benjamin J

    2015-11-01

    Patient-specific gait optimizations capable of predicting post-treatment changes in joint motions and loads could improve treatment design for gait-related disorders. To maximize potential clinical utility, such optimizations should utilize full-body three-dimensional patient-specific musculoskeletal models, generate dynamically consistent gait motions that reproduce pretreatment marker measurements closely, and achieve accurate foot motion tracking to permit deformable foot-ground contact modeling. This study enhances an existing residual elimination algorithm (REA) Remy, C. D., and Thelen, D. G., 2009, “Optimal Estimation of Dynamically Consistent Kinematics and Kinetics for Forward Dynamic Simulation of Gait,” ASME J. Biomech. Eng., 131(3), p. 031005) to achieve all three requirements within a single gait optimization framework. We investigated four primary enhancements to the original REA: (1) manual modification of tracked marker weights, (2) automatic modification of tracked joint acceleration curves, (3) automatic modification of algorithm feedback gains, and (4) automatic calibration of model joint and inertial parameter values. We evaluated the enhanced REA using a full-body three-dimensional dynamic skeletal model and movement data collected from a subject who performed four distinct gait patterns: walking, marching, running, and bounding. When all four enhancements were implemented together, the enhanced REA achieved dynamic consistency with lower marker tracking errors for all segments, especially the feet (mean root-mean-square (RMS) errors of 3.1 versus 18.4 mm), compared to the original REA. When the enhancements were implemented separately and in combinations, the most important one was automatic modification of tracked joint acceleration curves, while the least important enhancement was automatic modification of algorithm feedback gains. The enhanced REA provides a framework for future gait optimization studies that seek to predict subject-specific post-treatment gait patterns involving large changes in foot-ground contact patterns made possible through deformable foot-ground contact models. PMID:26299394

  6. Botulinum Toxin Type A Injection for Spastic Equinovarus Foot in Children with Spastic Cerebral Palsy: Effects on Gait and Foot Pressure Distribution

    PubMed Central

    Choi, Ja Young; Jung, Soojin; Rha, Dong-wook

    2016-01-01

    Purpose To investigate the effect of intramuscular Botulinum toxin type A (BoNT-A) injection on gait and dynamic foot pressure distribution in children with spastic cerebral palsy (CP) with dynamic equinovarus foot. Materials and Methods Twenty-five legs of 25 children with CP were investigated in this study. BoNT-A was injected into the gastrocnemius (GCM) and tibialis posterior (TP) muscles under the guidance of ultrasonography. The effects of the toxin were clinically assessed using the modified Ashworth scale (MAS) and modified Tardieu scale (MTS), and a computerized gait analysis and dynamic foot pressure measurements using the F-scan system were also performed before injection and at 1 and 4 months after injection. Results Spasticity of the ankle plantar-flexor in both the MAS and MTS was significantly reduced at both 1 and 4 months after injection. On dynamic foot pressure measurements, the center of pressure index and coronal index, which represent the asymmetrical weight-bearing of the medial and lateral columns of the foot, significantly improved at both 1 and 4 months after injection. The dynamic foot pressure index, total contact area, contact length and hind foot contact width all increased at 1 month after injection, suggesting better heel contact. Ankle kinematic data were significantly improved at both 1 and 4 months after injection, and ankle power generation was significantly increased at 4 months after injection compared to baseline data. Conclusion Using a computerized gait analysis and foot scan, this study revealed significant benefits of BoNT-A injection into the GCM and TP muscles for dynamic equinovarus foot in children with spastic CP. PMID:26847306

  7. The Gait Disorder in Downbeat Nystagmus Syndrome

    PubMed Central

    Schniepp, Roman; Wuehr, Max; Huth, Sabrina; Pradhan, Cauchy; Schlick, Cornelia; Brandt, Thomas; Jahn, Klaus

    2014-01-01

    Background Downbeat nystagmus (DBN) is a common form of acquired fixation nystagmus with key symptoms of oscillopsia and gait disturbance. Gait disturbance could be a result of impaired visual feedback due to the involuntary ocular oscillations. Alternatively, a malfunction of cerebellar locomotor control might be involved, since DBN is considered a vestibulocerebellar disorder. Methods Investigation of walking in 50 DBN patients (age 7211 years, 23 females) and 50 healthy controls (HS) (age 7011 years, 23 females) using a pressure sensitive carpet (GAITRite). The patient cohort comprised subjects with only ocular motor signs (DBN) and subjects with an additional limb ataxia (DBNCA). Gait investigation comprised different walking speeds and walking with eyes closed. Results In DBN, gait velocity was reduced (p<0.001) with a reduced stride length (p<0.001), increased base of support (p<0.050), and increased double support (p<0.001). Walking with eyes closed led to significant gait changes in both HS and DBN. These changes were more pronounced in DBN patients (p<0.001). Speed-dependency of gait variability revealed significant differences between the subgroups of DBN and DBNCA (p<0.050). Conclusions (I) Impaired visual control caused by involuntary ocular oscillations cannot sufficiently explain the gait disorder. (II) The gait of patients with DBN is impaired in a speed dependent manner. (III) Analysis of gait variability allows distinguishing DBN from DBNCA: Patients with pure DBN show a speed dependency of gait variability similar to that of patients with afferent vestibular deficits. In DBNCA, gait variability resembles the pattern found in cerebellar ataxia. PMID:25140517

  8. Journal bearing

    DOEpatents

    Menke, John R.; Boeker, Gilbert F.

    1976-05-11

    1. An improved journal bearing comprising in combination a non-rotatable cylindrical bearing member having a first bearing surface, a rotatable cylindrical bearing member having a confronting second bearing surface having a plurality of bearing elements, a source of lubricant adjacent said bearing elements for supplying lubricant thereto, each bearing element consisting of a pair of elongated relatively shallowly depressed surfaces lying in a cylindrical surface co-axial with the non-depressed surface and diverging from one another in the direction of rotation and obliquely arranged with respect to the axis of rotation of said rotatable member to cause a flow of lubricant longitudinally along said depressed surfaces from their distal ends toward their proximal ends as said bearing members are rotated relative to one another, each depressed surface subtending a radial angle of less than 360.degree., and means for rotating said rotatable bearing member to cause the lubricant to flow across and along said depressed surfaces, the flow of lubricant being impeded by the non-depressed portions of said second bearing surface to cause an increase in the lubricant pressure.

  9. Variability and similarity of gait as evaluated by joint angles: implications for forensic gait analysis.

    PubMed

    Yang, Sylvia X M; Larsen, Peter K; Alkjr, Tine; Simonsen, Erik B; Lynnerup, Niels

    2014-03-01

    Closed-circuit television (CCTV) footage is used in criminal investigations to compare perpetrators with suspects. Usually, incomplete gait cycles are collected, making evidential gait analysis challenging. This study aimed to analyze the discriminatory power of joint angles throughout a gait cycle. Six sets from 12 men were collected. For each man, a variability range VR (mean 1SD) of a specific joint angle at a specific time point (a gait cycle was 100 time points) was calculated. In turn, each individual was compared with the 11 others, and whenever 1 of these 11 had a value within this individuals VR, it counted as positive. By adding the positives throughout the gait cycle, we created simple bar graphs; tall bars indicated a small discriminatory power, short bars indicated a larger one. The highest discriminatory power was at time points 6080 in the gait cycle. We show how our data can assess gait data from an actual case. PMID:24745080

  10. The Inhibition of Subchondral Bone Lesions Significantly Reversed the Weight-Bearing Deficit and the Overexpression of CGRP in DRG Neurons, GFAP and Iba-1 in the Spinal Dorsal Horn in the Monosodium Iodoacetate Induced Model of Osteoarthritis Pain

    PubMed Central

    Liu, Ming; Zhao, Xin; Wang, Xiaoqing; Li, Yang; Mao, Yuanqing; Zhu, Zhenan

    2013-01-01

    Background Chronic pain is the most prominent and disabling symptom of osteoarthritis (OA). Clinical data suggest that subchondral bone lesions contribute to the occurrence of joint pain. The present study investigated the effect of the inhibition of subchondral bone lesions on joint pain. Methods Osteoarthritic pain was induced by an injection of monosodium iodoacetate (MIA) into the rat knee joint. Zoledronic acid (ZOL), a third generation of bisphosphonate, was used to inhibit subchondral bone lesions. Joint histomorphology was evaluated using X-ray micro computed tomography scanning and hematoxylin-eosin staining. The activity of osteoclast in subchondral bone was evaluated using tartrate-resistant acid phosphatase staining. Joint pain was evaluated using weight-bearing asymmetry, the expression of calcitonin gene-related peptide (CGRP) in the dorsal root ganglion (DRG), and spinal glial activation status using glial fibrillary acidic protein (GFAP) and ionized calcium binding adaptor molecule-1 (Iba-1) immunofluorescence. Afferent neurons in the DRGs that innervated the joints were identified using retrograde fluorogold labeling. Results MIA injections induced significant histomorphological alterations and joint pain. The inhibition of subchondral bone lesions by ZOL significantly reduced the MIA-induced weight-bearing deficit and overexpression of CGRP in DRG neurons, GFAP and Iba-1 in the spinal dorsal horn at 3 and 6 weeks after MIA injection; however, joint swelling and synovial reaction were unaffected. Conclusions The inhibition of subchondral bone lesions alleviated joint pain. Subchondral bone lesions should be a key target in the management of osteoarthritic joint pain. PMID:24204985

  11. Testing and Lubrication for Single Race Bearings

    SciTech Connect

    Steinhoff, R.G.

    1998-03-04

    Three ES and H-compatible lubricants (Environment, Safety and Health) for single race bearing applications and one hybrid-material single race bearings were evaluated and compared against single race bearings with trichlorotrifluoroethane (Freon) deposition of low molecular weight polytetrafluoroethylene (PTFE) bearing lubricant extracted from Vydax{trademark}. Vydax is a product manufactured by DuPont consisting of various molecular weights of PTFE suspended in trichlorotrifluoroethane (Freon), which is an ozone-depleting solvent. Vydax has been used as a bearing lubricant in stronglink mechanisms since 1974. Hybrid bearings with silicon nitride balls and molded glass-nylon-Teflon retainers, bearings lubricated with titanium carbide (TiC) on the balls, bearings lubricated with sputtered MoS{sub 2} on races and retainers, and bearings lubricated with electrophoretically deposited MoS{sub 2} were evaluated. The bearings were maintained in a preloaded state in bearing cartridges during cycling and vibration tests. Bearings with electrophoretically deposited MoS{sub 2} performed as well as bearings lubricated with Vydax and were the best performing candidate. All candidates were suitable for low preload applications. Bearings with TiC coated balls and bearings lubricated with sputtered MoS{sub 2} on the races and retainers performed well at high preloads, though not as well as bearings lubricated with electrophoretic deposition of MoS{sub 2}. Bearings with silicon nitride balls were not suitable for high preload applications.

  12. Motor programmes for the termination of gait in humans: organisation and velocity-dependent adaptation

    PubMed Central

    Crenna, Paolo; Cuong, Do Manh; Brénière, Yvon

    2001-01-01

    The organisation of the muscular activities responsible for the termination of gait, their modulation as a function of the rate of progression and the associated mechanical effects were investigated in normal adults, using EMG, force plate and kinematic recordings. In particular, the braking actions in reaction to a visual cue presented at the instant of heel-strike were analysed quantitatively, with a focus on representative leg and thigh muscles of the weight-supporting (stance) and oscillating (swing) limb, during walk-and-stop trials performed at three different velocities. In the stance limb, the EMG associated with braking started approximately 150 ms after the stop signal and, on average, displayed a distal-to-proximal activation sequence that primarily involved the posterior muscle groups (soleus, SOL, and hamstring, HAM). With the exception of SOL, which showed a single EMG burst, EMG patterns consisted of two or three progressively larger components occurring reciprocally in antagonistic muscles. Increasing walking speed yielded a significant reduction of the activity in distal muscles, and a simultaneous increment in proximal muscles. The mechanical effect of the earlier braking actions, estimated from the backward-directed wave of the horizontal ground reaction force, decreased in a velocity-dependent manner. In the swing limb the braking activities began approximately 330 ms after the stop signal and, on average, revealed a proximal-to-distal activation sequence with the extensor groups (quadriceps, QUAD, and SOL) playing a prominent role. They always consisted of single EMG bursts, largely co-activated in the antagonist muscles. The onset latencies of the individual components showed a close correlation, and the spatio-temporal parameters were always scaled in parallel. Unlike the stance limb, the mechanical braking action associated with the final contact of the swing limb increased with walking speed. The results indicate that the muscle synergies responsible for the rapid termination of gait in response to a ground-contact visual cue are produced by a relatively flexible set of motor commands modulated according to different velocity-dependent strategies in the weight-bearing limb, and by a single, fairly robust motor programme in the swing limb. Mechanical constraints related to the relative position of the centre of foot pressure and centre of body mass at the time the braking commands begin to affect external forces, may condition the difference between the two sides of the body. PMID:11744777

  13. Average Gait Differential Image Based Human Recognition

    PubMed Central

    Chen, Jinyan; Liu, Jiansheng

    2014-01-01

    The difference between adjacent frames of human walking contains useful information for human gait identification. Based on the previous idea a silhouettes difference based human gait recognition method named as average gait differential image (AGDI) is proposed in this paper. The AGDI is generated by the accumulation of the silhouettes difference between adjacent frames. The advantage of this method lies in that as a feature image it can preserve both the kinetic and static information of walking. Comparing to gait energy image (GEI), AGDI is more fit to representation the variation of silhouettes during walking. Two-dimensional principal component analysis (2DPCA) is used to extract features from the AGDI. Experiments on CASIA dataset show that AGDI has better identification and verification performance than GEI. Comparing to PCA, 2DPCA is a more efficient and less memory storage consumption feature extraction method in gait based recognition. PMID:24895648

  14. Gait Recognition Using Image Self-Similarity

    NASA Astrophysics Data System (ADS)

    BenAbdelkader, Chiraz; Cutler, Ross G.; Davis, Larry S.

    2004-12-01

    Gait is one of the few biometrics that can be measured at a distance, and is hence useful for passive surveillance as well as biometric applications. Gait recognition research is still at its infancy, however, and we have yet to solve the fundamental issue of finding gait features which at once have sufficient discrimination power and can be extracted robustly and accurately from low-resolution video. This paper describes a novel gait recognition technique based on the image self-similarity of a walking person. We contend that the similarity plot encodes a projection of gait dynamics. It is also correspondence-free, robust to segmentation noise, and works well with low-resolution video. The method is tested on multiple data sets of varying sizes and degrees of difficulty. Performance is best for fronto-parallel viewpoints, whereby a recognition rate of 98% is achieved for a data set of 6 people, and 70% for a data set of 54 people.

  15. Research on gait-based human identification

    NASA Astrophysics Data System (ADS)

    Li, Youguo

    Gait recognition refers to automatic identification of individual based on his/her style of walking. This paper proposes a gait recognition method based on Continuous Hidden Markov Model with Mixture of Gaussians(G-CHMM). First, we initialize a Gaussian mix model for training image sequence with K-means algorithm, then train the HMM parameters using a Baum-Welch algorithm. These gait feature sequences can be trained and obtain a Continuous HMM for every person, therefore, the 7 key frames and the obtained HMM can represent each person's gait sequence. Finally, the recognition is achieved by Front algorithm. The experiments made on CASIA gait databases obtain comparatively high correction identification ratio and comparatively strong robustness for variety of bodily angle.

  16. Grizzly bear

    USGS Publications Warehouse

    Schwartz, C.C.; Miller, S.D.; Haroldson, M.A.

    2003-01-01

    The grizzly bear inspires fear, awe, and respect in humans to a degree unmatched by any other North American wild mammal. Like other bear species, it can inflict serious injury and death on humans and sometimes does. Unlike the polar bear (Ursus maritimus) of the sparsely inhabited northern arctic, however, grizzly bears still live in areas visited by crowds of people, where presence of the grizzly remains physically real and emotionally dominant. A hike in the wilderness that includes grizzly bears is different from a stroll in a forest from which grizzly bears have been purged; nighttime conversations around the campfire and dreams in the tent reflect the presence of the great bear. Contributing to the aura of the grizzly bear is the mixture of myth and reality about its ferocity. unpredictable disposition, large size, strength, huge canines, long claws, keen senses, swiftness, and playfulness. They share characteristics with humans such as generalist life history strategies. extended periods of maternal care, and omnivorous diets. These factors capture the human imagination in ways distinct from other North American mammals. Precontact Native American legends reflected the same fascination with the grizzly bear as modern stories and legends (Rockwell 1991).

  17. Thrust bearing

    NASA Technical Reports Server (NTRS)

    Anderson, W. J. (Inventor)

    1976-01-01

    A gas lubricated thrust bearing is described which employs relatively rigid inwardly cantilevered spokes carrying a relatively resilient annular member or annulus. This annulus acts as a beam on which are mounted bearing pads. The resilience of the beam mount causes the pads to accept the load and, with proper design, responds to a rotating thrust-transmitting collar by creating a gas film between the pads and the thrust collar. The bearing may be arranged for load equalization thereby avoiding the necessity of gimbal mounts or the like for the bearing. It may also be arranged to respond to rotation in one or both directions.

  18. Aerospace applications of magnetic bearings

    NASA Technical Reports Server (NTRS)

    Downer, James; Goldie, James; Gondhalekar, Vijay; Hockney, Richard

    1994-01-01

    Magnetic bearings have traditionally been considered for use in aerospace applications only where performance advantages have been the primary, if not only, consideration. Conventional wisdom has been that magnetic bearings have certain performance advantages which must be traded off against increased weight, volume, electric power consumption, and system complexity. These perceptions have hampered the use of magnetic bearings in many aerospace applications because weight, volume, and power are almost always primary considerations. This paper will review progress on several active aerospace magnetic bearings programs at SatCon Technology Corporation. The magnetic bearing programs at SatCon cover a broad spectrum of applications including: a magnetically-suspended spacecraft integrated power and attitude control system (IPACS), a magnetically-suspended momentum wheel, magnetic bearings for the gas generator rotor of a turboshaft engine, a vibration-attenuating magnetic bearing system for an airborne telescope, and magnetic bearings for the compressor of a space-rated heat pump system. The emphasis of these programs is to develop magnetic bearing technologies to the point where magnetic bearings can be truly useful, reliable, and well tested components for the aerospace community.

  19. Gait Dysfunction in Mild Cognitive Impairment Syndromes

    PubMed Central

    Verghese, Joe; Robbins, Matthew; Holtzer, Roee; Zimmerman, Molly; Wang, Cuiling; Xue, Xiaonan; Lipton, Richard B.

    2008-01-01

    OBJECTIVES To conduct a systematic clinical and quantitative assessment of gait in older adults with mild cognitive impairment (MCI) syndromes. DESIGN Cross-sectional. SETTING Einstein Aging Study, a community-based longitudinal aging study. PARTICIPANTS Fifty-four individuals with amnestic MCI (a-MCI), 62 with nonamnestic-MCI (na-MCI), and 295 healthy controls identified from the Einstein Aging Study participants. MEASUREMENTS Comparison of clinical and quantitative gait performance in subjects with MCI subtypes with that of cognitively normal older adults. RESULTS Neurological gaits were more common in a-MCI (31.5%, P = .008) but not in na-MCI (19.4%, P = .55), than in controls (16.3%). Quantitative gait in multiple parameters was worse in both MCI subtypes than in controls. Factor analysis revealed three independent factors representing pace, rhythm, and variability. Subjects with a-MCI had worse rhythm and variability scores than those with na-MCI and controls. Subjects with na-MCI had worse performance on the pace domain than the other two groups. Subjects with MCI and gait abnormalities had higher disability scores than subjects with MCI without gait abnormalities. CONCLUSION Gait dysfunction is common in older individuals with amnestic and nonamnestic subtypes of MCI. PMID:18482293

  20. Gait patterns in COPD: the Rotterdam Study.

    PubMed

    Lahousse, Lies; Verlinden, Vincentius J A; van der Geest, Jos N; Joos, Guy F; Hofman, Albert; Stricker, Bruno H C; Brusselle, Guy G; Ikram, M Arfan

    2015-07-01

    Gait disturbances in patients with chronic obstructive pulmonary disease (COPD) may lead to disability and falls. As studies assessing gait kinematics in COPD are sparse, we investigated associations of COPD with various gait domains and explored a potential link with falling. Gait was measured within the prospective, population-based Rotterdam Study (age ≥55 years) using an electronic walkway and summarised into seven gait domains: Rhythm, Variability, Phases, Pace, Tandem, Turning and Base of Support. Rhythm is a temporal gait aspect that includes cadence and reflects how quickly steps are taken. Persons with COPD (n=196) exhibited worse Rhythm (-0.21 SD, 95% CI -0.36- -0.06 SD) compared with persons with normal lung function (n=898), independent of age, sex, height, education, smoking or analgesic use, especially when dyspnoea and severe airflow limitation or frequent exacerbations (Global Initiative for Chronic Obstructive Lung Disease group D: -0.83 SD, 95% CI -1.25- -0.41 SD) were present. A lower forced expiratory volume in 1 s was associated with worse Rhythm and Pace, including lower cadence and gait velocity, respectively. Importantly, fallers with COPD had significantly worse Rhythm than nonfallers with COPD. This study demonstrates that persons with COPD exhibit worse Rhythm, especially fallers with COPD. The degree of Rhythm deterioration was associated with the degree of airflow limitation, symptoms and frequency of exacerbations. PMID:25700390

  1. Polar Bear

    USGS Publications Warehouse

    Amstrup, S.D.; DeMaster

    1988-01-01

    Polar bears are long-lived, late-maturing carnivores that have relatively low rates of reproduction and natural mortality. Their populations are susceptible to disturbance from human activities, such as the exploration and development of mineral resources or hunting. Polar bear populations have been an important renewable resource available to coastal communities throughout the Arctic for thousands of years.

  2. Duck gait: Relationship to hip angle, bone ash, bone density, and morphology.

    PubMed

    Robison, Cara I; Rice, Meredith; Makagon, Maja M; Karcher, Darrin M

    2015-05-01

    The rapid growth meat birds, including ducks, undergo requires skeletal integrity; however, fast growth may not be conducive to adequate bone structure. A relationship likely exists between skeletal changes and duck mobility. Reduced mobility in meat ducks may have impacts on welfare and production. This study examined the relationships among gait score, bone parameters, and hip angle. Commercial Pekin ducks, ages 14 d (n = 100), 21 d (n = 100), and 32 d (n = 100) were weighed and gait scored with a 3-point gait score system by an observer as they walked over a Tekscan gait analysis system. Gait was scored as GS0, GS1, or GS2 with a score of GS0 defined as good walking ability and a score of GS2 as poorest walking ability. Ducks were humanely euthanized, full body scanned using quantitative computed tomography (QCT), and the right femur and tibia were extracted. Leg bones were cleaned, measured, fat extracted, and ashed. QCT scans were rendered to create computerized 3D models where pelvic hip angles and bone density were measured. Statistical analysis was conducted using PROC MIXED with age and gait score in the model. Body weight increased with age, but within an age, body weight decreased as walking ability became worse (P < 0.01). As expected, linear increases in tibia and femur bone width and length were observed as the ducks aged (P < 0.01). Right and left hip angle increased with duck age (P < 0.01). Additionally, ducks with a GS2 had wider hip angles opposed to ducks with a GS0 (P < 0.01). Bone density increased linearly with both age and gait score (P < 0.05). Femur ash content was lowest in 32-day-old ducks and ducks with GS1 and GS2 (P < 0.0001). Tibia ash content increased with age, but decreased as gait score increased (P < 0.001). The observation that right hip angle changed with gait scores merits further investigation into the relationship between duck mobility and skeletal changes during growth. PMID:25810406

  3. Gait recognition based on Gabor wavelets and modified gait energy image for human identification

    NASA Astrophysics Data System (ADS)

    Huang, Deng-Yuan; Lin, Ta-Wei; Hu, Wu-Chih; Cheng, Chih-Hsiang

    2013-10-01

    This paper proposes a method for recognizing human identity using gait features based on Gabor wavelets and modified gait energy images (GEIs). Identity recognition by gait generally involves gait representation, extraction, and classification. In this work, a modified GEI convolved with an ensemble of Gabor wavelets is proposed as a gait feature. Principal component analysis is then used to project the Gabor-wavelet-based gait features into a lower-dimension feature space for subsequent classification. Finally, support vector machine classifiers based on a radial basis function kernel are trained and utilized to recognize human identity. The major contributions of this paper are as follows: (1) the consideration of the shadow effect to yield a more complete segmentation of gait silhouettes; (2) the utilization of motion estimation to track people when walkers overlap; and (3) the derivation of modified GEIs to extract more useful gait information. Extensive performance evaluation shows a great improvement of recognition accuracy due to the use of shadow removal, motion estimation, and gait representation using the modified GEIs and Gabor wavelets.

  4. Cryogenic Magnetic Bearing Test Facility (CMBTF)

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The Cryogenic Magnetic Bearing Test Facility (CMBTF) was designed and built to evaluate compact, lightweight magnetic bearings for use in the SSME's (space shuttle main engine) liquid oxygen and liquid hydrogen turbopumps. State of the art and tradeoff studies were conducted which indicated that a hybrid permanent magnet bias homopolar magnetic bearing design would be smaller, lighter, and much more efficient than conventional industrial bearings. A test bearing of this type was designed for the test rig for use at both room temperature and cryogenic temperature (-320 F). The bearing was fabricated from state-of-the-art materials and incorporated into the CMBTF. Testing at room temperature was accomplished at Avcon's facility. These preliminary tests indicated that this magnetic bearing is a feasible alternative to older bearing technologies. Analyses showed that the hybrid magnetic bearing is one-third the weight, considerably smaller, and uses less power than previous generations of magnetic bearings.

  5. The connection between anthropometry and gait harmony unveiled through the lens of the golden ratio.

    PubMed

    Iosa, Marco; Morone, Giovanni; Bini, Fabiano; Fusco, Augusto; Paolucci, Stefano; Marinozzi, Franco

    2016-01-26

    In nature, many systems have a harmonic organization due to their fractal structure related to an irrational number called golden ratio. That is a constant proportion found in phases of human gait cycle, and is also found in the lengths of human body segments. In this study we tested if artificial alterations in anthropometric proportions may alter gait proportions. Twenty healthy subjects (29.15±5.66years) were enrolled in this study and asked to walk normally and with special shoes altering their anthropometric proportions. Further, to test if the relationship between gait phases and anthropometry could be due to the pendular mechanism of walking, subjects were also asked to walk with extra masses located on their shanks. Results showed that the artificial alteration of body segment proportions affected the gait ratio based on the proportion of time between stance and swing (p=0.015). Conversely, no changes occurred during walking in weighted condition (p=0.394). These results confirm the connection between anthropometric proportions and gait ratio, and suggest the idea that humans may have evolved into the actual anthropometric proportions for favoring a walking having a golden ratio based harmony, but research is required to verify this hypothesis. PMID:26700875

  6. The effect of osteochondral regeneration using polymer constructs and continuous passive motion therapy in the lower weight-bearing zone of femoral trocheal groove in rabbits.

    PubMed

    Chang, Nai-Jen; Lin, Chih-Chan; Li, Chien-Feng; Su, Kai; Yeh, Ming-Long

    2013-02-01

    Remedying patellofemoral osteochondral defects using clinical therapy remains challenging. Construct-based and cell-based regenerative medicine with in vitro physical stimuli has been progressively implemented. However, the effect of physical stimuli in situ in knee joints with degradable constructs is still not well-documented. Therefore, we studied whether it was practical to achieve articular cartilage repair using a poly(lactic-co-glycolic acid) (PLGA) construct in addition to early short-term continuous passive motion (CPM) for treatment of full-thickness osteochondral defects in the lower-weigh bearing (LWB) zone of the femoral trocheal groove. Twenty-six rabbits were randomly allocated into either intermittent active motion (IAM) or CPM treatment groups with or without PLGA constructs, termed PLGA construct-implanted (PCI) and empty defect knee models, respectively. Gross observation, histology, inflammatory cells, which were identified using H&E staining, total collagen and alignment, studied qualitatively using Masson's trichrome staining, glycosaminoglycan (GAG), identified using Alcian blue staining, and newly formed bone, observed using micro-CT, were evaluated at 4 and 12 weeks after surgery. Repair of osteochondral defects in the PCI-CPM group was more promising than all other groups. The better osteochondral defect repair in the PCI-CPM group corresponded to smooth cartilage surfaces, no inflammatory reaction, hyaline cartilaginous tissues composition, sound collagen alignment with positive collagen type II expression, higher GAG content, mature bone regeneration with osteocyte, clear tidemark formation, and better degradation of PLGA. In summary, the use of a simple PLGA construct coupled with passive motion promotes positive healing and may be a promising clinical intervention for osteochondral regeneration in LWB defects. PMID:22987137

  7. Hydrodynamic squeeze-film bearings for gyroscopes

    NASA Technical Reports Server (NTRS)

    Chiang, T.; Smith, R. L.

    1970-01-01

    Experimental tests are conducted on squeeze-film bearings by applying electricity to piezoelectric ceramics, causing vibrations at thousands or millions of Hz that are amplified and transmitted to the bearing. Rotor operation through 24,000 rpm without whirl instability proved bearing ability to support rotor weight without hydrodynamic action.

  8. A new galloping gait in an insect.

    PubMed

    Smolka, Jochen; Byrne, Marcus J; Scholtz, Clarke H; Dacke, Marie

    2013-10-21

    An estimated three million insect species all walk using variations of the alternating tripod gait [1]. At any one time, these animals hold one stable triangle of legs steady while swinging the opposite triangle forward. Here, we report the discovery that three different flightless desert dung beetles use an additional gallop-like gait, which has never been described in any insect before. Like a bounding hare, the beetles propel their body forward by synchronously stepping with both middle legs and then both front legs. Surprisingly, this peculiar galloping gait delivers lower speeds than the alternating tripod gait. Why these beetles have shifted so radically away from the most widely used walking style on our planet is as yet unknown. PMID:24156806

  9. Walking (Gait), Balance, and Coordination Problems

    MedlinePlus

    ... the weaker leg through), compensatory hip hike, trunk lean or circumduction (swinging leg out to the side). ... messaging within the nervous system) Treatment and self-management strategies Most gait problems can be helped to ...

  10. Toward understanding the limits of gait recognition

    NASA Astrophysics Data System (ADS)

    Liu, Zongyi; Malave, Laura; Osuntogun, Adebola; Sudhakar, Preksha; Sarkar, Sudeep

    2004-08-01

    Most state of the art video-based gait recognition algorithms start from binary silhouettes. These silhouettes, defined as foreground regions, are usually detected by background subtraction methods, which results in holes or missed parts due to similarity of foreground and background color, and boundary errors due to video compression artifacts. Errors in low-level representation make it hard to understand the effect of certain conditions, such as surface and time, on gait recognition. In this paper, we present a part-level, manual silhouette database consisting of 71 subjects, over one gait cycle, with differences in surface, shoe-type, carrying condition, and time. We have a total of about 11,000 manual silhouette frames. The purpose of this manual silhouette database is twofold. First, this is a resource that we make available at http://www.GaitChallenge.org for use by the gait community to test and design better silhouette detection algorithms. These silhouettes can also be used to learn gait dynamics. Second, using the baseline gait recognition algorithm, which was specified along with the HumanID Gait Challenge problem, we show that performance from manual silhouettes is similar and only sometimes better than that from automated silhouettes detected by statistical background subtraction. Low performances when comparing sequences with differences in walking surfaces and time-variation are not fully explained by silhouette quality. We also study the recognition power in each body part and show that recognition based on just the legs is equal to that from the whole silhouette. There is also significant recognition power in the head and torso shape.

  11. Canine hip extension range during gait.

    PubMed

    van der Walt, A M; Stewart, A V; Joubert, K E; Bekker, P

    2008-12-01

    Assessment of canine gait is frequently used by veterinary clinicians to establish the presence of orthopaedic pain. As up to 30% of canine orthopaedic conditions affect the pelvic limb, knowledge of pelvic limb biomechanics during gait is very important. Previous studies have investigated the biomechanics at the tarsus and stifle, but little information is available regarding hip motion during gait. The aim of this study was to determine the maximum hip extension range achieved during the stance phase of gait in normal canines. In addition, this study aimed to determine the difference between maximum passive hip extension and maximum hip extension during gait. Using a sample of 30 morphologically similar normal dogs, mean maximum passive hip extension was measured using a goniometer and mean maximum hip extension range during gait was determined videographically. Inter- and intra-assessor reliability studies performed at the start of the study showed that the measurement tools and techniques used in this study were valid and reliable. The goniometric data showed that mean maximum passive hip extension range was 162.44 degrees (+/-3.94) with no significant difference between the left and the right hind limbs. The videographic data showed that mean maximum hip extension range during gait was 119.9 degrees (+/-9.26) with no significant difference between the left and right hind limbs. The results of this study provided reference values for active and passive hip extension range and showed that the degree of hip extension range required for normal gait is significantly less than maximum passive hip extension range. PMID:19496317

  12. PAGAS: Portable and Accurate Gait Analysis System.

    PubMed

    Wagner, Rojay; Ganz, Aura

    2012-01-01

    Gait analysis systems are powerful tools in the monitoring and rehabilitation of many health conditions which result in an altered gait (such as Parkinson's disease and rheumatoid arthritis), along with the injury of lower limbs. However, current systems that provide accurate gait monitoring and analysis are large and expensive, and therefore are available only in professional settings. The goal of this research is to develop and test a Portable and Accurate Gait Analysis System, denoted PAGAS, which enables patients to monitor their own gait and track their progress and improvement over time. Moreover, PAGAS will enable therapists to follow the progress of their patients over time without the need for multiple visits required at a rehabilitation facility, thus saving significant healthcare costs. PAGAS includes footswitches and a micro-controller, which connects to an Android Smart-phone using Bluetooth communication. An application on the Smartphone analyzes the raw data to produce temporal gait parameters that are displayed to the user on a graphical user interface. PMID:23365885

  13. Gait Recognition Using Wearable Motion Recording Sensors

    NASA Astrophysics Data System (ADS)

    Gafurov, Davrondzhon; Snekkenes, Einar

    2009-12-01

    This paper presents an alternative approach, where gait is collected by the sensors attached to the person's body. Such wearable sensors record motion (e.g. acceleration) of the body parts during walking. The recorded motion signals are then investigated for person recognition purposes. We analyzed acceleration signals from the foot, hip, pocket and arm. Applying various methods, the best EER obtained for foot-, pocket-, arm- and hip- based user authentication were 5%, 7%, 10% and 13%, respectively. Furthermore, we present the results of our analysis on security assessment of gait. Studying gait-based user authentication (in case of hip motion) under three attack scenarios, we revealed that a minimal effort mimicking does not help to improve the acceptance chances of impostors. However, impostors who know their closest person in the database or the genders of the users can be a threat to gait-based authentication. We also provide some new insights toward the uniqueness of gait in case of foot motion. In particular, we revealed the following: a sideway motion of the foot provides the most discrimination, compared to an up-down or forward-backward directions; and different segments of the gait cycle provide different level of discrimination.

  14. Gait Partitioning Methods: A Systematic Review

    PubMed Central

    Taborri, Juri; Palermo, Eduardo; Rossi, Stefano; Cappa, Paolo

    2016-01-01

    In the last years, gait phase partitioning has come to be a challenging research topic due to its impact on several applications related to gait technologies. A variety of sensors can be used to feed algorithms for gait phase partitioning, mainly classifiable as wearable or non-wearable. Among wearable sensors, footswitches or foot pressure insoles are generally considered as the gold standard; however, to overcome some inherent limitations of the former, inertial measurement units have become popular in recent decades. Valuable results have been achieved also though electromyography, electroneurography, and ultrasonic sensors. Non-wearable sensors, such as opto-electronic systems along with force platforms, remain the most accurate system to perform gait analysis in an indoor environment. In the present paper we identify, select, and categorize the available methodologies for gait phase detection, analyzing advantages and disadvantages of each solution. Finally, we comparatively examine the obtainable gait phase granularities, the usable computational methodologies and the optimal sensor placements on the targeted body segments. PMID:26751449

  15. Imaging gait disorders in parkinsonism: a review.

    PubMed

    Maillet, Audrey; Pollak, Pierre; Debû, Bettina

    2012-10-01

    Gait difficulties--including freezing of gait--are frequent and disabling symptoms of advanced Parkinson's disease and other parkinsonian syndromes. They respond poorly to current medical and surgical treatments, making patient management very difficult. The underlying pathophysiology remains largely unknown. The late onset of levodopa resistance of Parkinson's disease gait abnormalities has been suggested to result from the progressive extension of the degenerative process to non-dopaminergic structures involved in locomotion, such as cortico-frontal and brainstem networks. Deficiencies in other neurotransmission systems, involving acetylcholine, serotonin or norepinephrine, have also been evoked. Neuroimaging tools appear well suited to decipher the cerebral substrates of parkinsonian gait disorders and their modulation by dopaminergic medication or deep brain stimulation. Here the main functional and metabolic neuroimaging studies aimed at identifying these cerebral networks are reviewed, in both healthy subjects and parkinsonian patients. After a brief overview of the physiology and pathophysiology of gait control, the methodology, main results and limits of the studies published to date are examined. The most promising methods to examine gait difficulties and their response to currently available treatments are then discussed. PMID:22773859

  16. Gait Partitioning Methods: A Systematic Review.

    PubMed

    Taborri, Juri; Palermo, Eduardo; Rossi, Stefano; Cappa, Paolo

    2016-01-01

    In the last years, gait phase partitioning has come to be a challenging research topic due to its impact on several applications related to gait technologies. A variety of sensors can be used to feed algorithms for gait phase partitioning, mainly classifiable as wearable or non-wearable. Among wearable sensors, footswitches or foot pressure insoles are generally considered as the gold standard; however, to overcome some inherent limitations of the former, inertial measurement units have become popular in recent decades. Valuable results have been achieved also though electromyography, electroneurography, and ultrasonic sensors. Non-wearable sensors, such as opto-electronic systems along with force platforms, remain the most accurate system to perform gait analysis in an indoor environment. In the present paper we identify, select, and categorize the available methodologies for gait phase detection, analyzing advantages and disadvantages of each solution. Finally, we comparatively examine the obtainable gait phase granularities, the usable computational methodologies and the optimal sensor placements on the targeted body segments. PMID:26751449

  17. Quantitative gait disturbances in older adults with cognitive impairments.

    PubMed

    Bridenbaugh, Stephanie A; Kressig, Reto W

    2014-01-01

    Gait is a complex motor task, initiated and governed by different areas of the brain. Studies have shown a clear association between gait and cognition. Impairments in both gait and cognition are prevalent in older adults. Older adults with gait impairment have an increased risk of developing cognitive impairments. Those with cognitive impairment often have gait impairments and more falls than cognitively healthy older adults. Recent studies have shown that quantitative gait analysis, particularly performed during dual task conditions, can detect gait deficits that cannot yet be seen by the naked eye, even to a trained specialist. Some studies have shown that such gait disturbances were measurable years before mild cognitive impairment or dementia or walking difficulties were clinically manifest. Quantitative gait analysis can provide early detection of gait and cognitive impairments as well as fall risk. Future quantitative gait studies may help distinguish dementia subtypes in early stages of the diseases. Early detection of gait and cognitive impairments would provide a better understanding of disease pathophysiology and progression. Early detection also allows the timely implementation of interventions with the ultimate goal of improving or maintaining mobility and functional independence for as long as possible. Quantitative gait analysis should be viewed as a clinical tool to aid diagnoses and treatment planning. This review examines the current literature on quantitatively measured gait impairment in older adults with mild cognitive impairment or a dementia subtype. PMID:24050167

  18. Foil bearings

    NASA Technical Reports Server (NTRS)

    Elrod, David A.

    1993-01-01

    The rolling element bearings (REB's) which support many turbomachinery rotors offer high load capacity, low power requirements, and durability. Two disadvantages of REB's are: (1) rolling or sliding contact within the bearing has life-limiting consequences; and (2) REB's provide essentially no damping. The REB's in the Space Shuttle Main Engine (SSME) turbopumps must sustain high static and dynamic loads, at high speeds, with a cryogenic fluid as lubricant and coolant. The pump end ball bearings limit the life of the SSME high pressure oxygen turbopump (HPOTP). Compliant foil bearing (CFB) manufacturers have proposed replacing turbopump REB's with CFB's CFB's work well in aircraft air cycle machines, auxiliary power units, and refrigeration compressors. In a CFB, the rotor only contracts the foil support structure during start up and shut down. CFB damping is higher than REB damping. However, the load capacity of the CFB is low, compared to a REB. Furthermore, little stiffness and damping data exists for the CFB. A rotordynamic analysis for turbomachinery critical speeds and stability requires the input of bearing stiffness and damping coefficients. The two basic types of CFB are the tension-dominated bearing and the bending-dominated bearing. Many investigators have analyzed and measured characteristics of tension-dominated foil bearings, which are applied principally in magnetic tape recording. The bending-dominated CFB is used more in rotating machinery. This report describes the first phase of a structural analysis of a bending-dominated, multileaf CFB. A brief discussion of CFB literature is followed by a description and results of the present analysis.

  19. Foil bearings

    NASA Astrophysics Data System (ADS)

    Elrod, David A.

    1993-11-01

    The rolling element bearings (REB's) which support many turbomachinery rotors offer high load capacity, low power requirements, and durability. Two disadvantages of REB's are: (1) rolling or sliding contact within the bearing has life-limiting consequences; and (2) REB's provide essentially no damping. The REB's in the Space Shuttle Main Engine (SSME) turbopumps must sustain high static and dynamic loads, at high speeds, with a cryogenic fluid as lubricant and coolant. The pump end ball bearings limit the life of the SSME high pressure oxygen turbopump (HPOTP). Compliant foil bearing (CFB) manufacturers have proposed replacing turbopump REB's with CFB's CFB's work well in aircraft air cycle machines, auxiliary power units, and refrigeration compressors. In a CFB, the rotor only contracts the foil support structure during start up and shut down. CFB damping is higher than REB damping. However, the load capacity of the CFB is low, compared to a REB. Furthermore, little stiffness and damping data exists for the CFB. A rotordynamic analysis for turbomachinery critical speeds and stability requires the input of bearing stiffness and damping coefficients. The two basic types of CFB are the tension-dominated bearing and the bending-dominated bearing. Many investigators have analyzed and measured characteristics of tension-dominated foil bearings, which are applied principally in magnetic tape recording. The bending-dominated CFB is used more in rotating machinery. This report describes the first phase of a structural analysis of a bending-dominated, multileaf CFB. A brief discussion of CFB literature is followed by a description and results of the present analysis.

  20. Gait training facilitates central drive to ankle dorsiflexors in children with cerebral palsy

    PubMed Central

    Petersen, Tue Hvass; Farmer, Simon Francis; Nielsen, Jens Bo

    2015-01-01

    Foot drop and toe walking are frequent concerns in children with cerebral palsy. The main underlying cause of these problems is early damage and lack of maturation of the corticospinal tract. In the present study we investigated whether 4 weeks of daily treadmill training with an incline may facilitate corticospinal transmission and improve the control of the ankle joint in children with cerebral palsy. Sixteen children with cerebral palsy (Gross Motor Classification System I:6, II:6, III:4) aged 5–14 years old, were recruited for the study. Evaluation of gait ability and intramuscular coherence was made twice before and twice after training with an interval of 1 month. Gait kinematics were recorded by 3D video analysis during treadmill walking with a velocity chosen by the child at the first evaluation. Foot pressure was measured by force sensitive foot soles during treadmill and over ground walking. EMG-EMG coherence was calculated from two separate electrode recordings placed over the tibialis anterior muscle. Training involved 30 min of walking daily on a treadmill with an incline for 30 days. Gait training was accompanied by significant increases in gait speed, incline on the treadmill, the maximal voluntary dorsiflexion torque, the number and amplitude of toe lifts late in the swing phase during gait and the weight exerted on the heel during the early stance phase of the gait cycle. EMG-EMG coherence in the beta and gamma frequency bands recorded from tibialis anterior muscle increased significantly when compared to coherence before training. The largest changes in coherence with training were observed for children <10 years of age. Importantly, in contrast to training-induced EMG increases, the increase in coherence was maintained at the follow-up measurement 1 month after training. Changes in the strength of coherence in the beta and gamma band were positively correlated with improvements in the subjects’ ability to lift the toes in the swing phase. These data show that daily intensive gait training increases beta and gamma oscillatory drive to ankle dorsiflexor motor neurons and that it improves toe lift and heel strike in children with cerebral palsy. We propose that intensive gait training may produce plastic changes in the corticospinal tract, which are responsible for improvements in gait function. PMID:25623137

  1. Gait dynamics in Parkinson's disease: Common and distinct behavior among stride length, gait variability, and fractal-like scaling

    NASA Astrophysics Data System (ADS)

    Hausdorff, Jeffrey M.

    2009-06-01

    Parkinson's disease (PD) is a common, debilitating neurodegenerative disease. Gait disturbances are a frequent cause of disability and impairment for patients with PD. This article provides a brief introduction to PD and describes the gait changes typically seen in patients with this disease. A major focus of this report is an update on the study of the fractal properties of gait in PD, the relationship between this feature of gait and stride length and gait variability, and the effects of different experimental conditions on these three gait properties. Implications of these findings are also briefly described. This update highlights the idea that while stride length, gait variability, and fractal scaling of gait are all impaired in PD, distinct mechanisms likely contribute to and are responsible for the regulation of these disparate gait properties.

  2. Classification of gait quality for biofeedback to improve heel-to-toe gait.

    PubMed

    Vadnerkar, Abhishek; Figueiredo, Sabrina; Mayo, Nancy E; Kearney, Robert E

    2014-01-01

    A feature of healthy gait is a clearly defined heel strike upon initial contact of the foot with the ground. However, a common consequence of ageing is deterioration of the heel first nature of gait towards a shuffling gait (flat foot at contact). Physiotherapy can be effective in correcting this but is costly and labour intensive. Gait rehabilitation could be accelerated with home exercise, guided by a biofeedback device that distinguishes between heel first and shuffling gait. This paper describes an algorithm that distinguishes between heel-to-toe gait and shuffling gait on the basis of angular velocity of the foot, using an inertial measurement unit. Measurements were made of normal and abnormal gait and used to develop an algorithm that distinguishes between good and bad steps. Results demonstrate very good algorithm performance, with a classification accuracy at the accuracy-optimal threshold of 92.7% when compared with physiotherapist labels. The sensitivity and specificity at this threshold are 84.4% and 97.5% respectively. These performance metrics suggest that this algorithm is usable in a biofeedback device. PMID:25570776

  3. Effects of obesity on gait pattern in young individuals with Down syndrome.

    PubMed

    Galli, Manuela; Cimolin, Veronica; Rigoldi, Chiara; Condoluci, Claudia; Albertini, Giorgio

    2015-03-01

    In individuals with Down syndrome (DS), the prevalence of obesity is widespread; despite this, there are no experimental studies on the effect of obesity on gait strategy in DS individuals. The aim of this study is to assess the clinical gait analysis of a group of obese individuals with DS and a group of nonobese individuals with DS to determine whether obesity produces a different gait pattern in these participants. In addition, although females and males share a similar mass, they are characterized by different fat distribution and/or accumulation; thus, the presence of differences between females and males within the two DS groups was investigated. Gait analysis data of a group of 78 young individuals with DS and 20 normal-weight participants in the 5-18-year age range were considered. Among DS individuals, 40 were classified as obese (obese DS group), whereas 38 were classified as normal weight (nonobese groups). A three-dimensional gait analysis was carried out using an optoelectronic system, force platforms and video recording. Spatiotemporal, kinematic and kinetic parameters were identified and calculated for each participant. Our results show that most of the parameters were similar in the two groups of DS participants; the only differences were in terms of stance duration, longer in the obese DS group and dorsiflexion ability during the swing phase, which was limited in the obese DS group. The two DS groups were significantly different in terms of ankle stiffness (Ka index): both groups were characterized by reduced values compared with the control group, but the obese group presented lower values with respect to nonobese participants. The data showed that females were characterized by significant modifications of gait pattern compared with males in both groups, in particular, at proximal levels, such as the hip and the pelvis. Our findings indicate that the presence of obesity exerts effects on gait pattern in DS individuals and in particular on ankle joint stiffness. These results may have special clinical relevance; the biomechanical comparison of gait in young obese and nonobese DS individuals may provide a basis for developing either specific or common rehabilitative strategies. PMID:25419690

  4. Correlation between balance and gait according to pelvic displacement in stroke patients.

    PubMed

    Kong, Seon Woong; Jeong, Yeon Woo; Kim, Jin Young

    2015-07-01

    [Purpose] The purpose of this study was to investigate the correlations of balance and gait according to pelvic displacement in stroke patients. [Subjects] The subjects of this study were 58 stroke patients who had been admitted to a hospital. [Methods] A Global Postural System was used to measure pelvic displacement. To measure the balance ability, a Tetrax balance system was used to measure the weight distribution index and stability index. Gait ability was measured during the 10-Meter Walking Test and Figure-of-8 Walk Test. [Results] The results of this study showed that was significant positive correlation between the anterior superior iliac spine height difference in pelvic displacement and the weight distribution index and significant positive correlation between the posterior superior iliac spine height difference and the stability index in the normal position with the eyes closed. Statistically significant positive correlation also was found between the anterior superior iliac spine height difference and the straight and curved gait ability. [Conclusion] The increased pelvic displacement in stroke patients results in a decrease in balance ability and gait speed. This suggests that control of pelvic displacement is necessary before functional training for patients with stroke. PMID:26311948

  5. Changes in plantar load distribution and gait pattern following foot drop correction in leprosy affected patients.

    PubMed

    Karmakar, Mrinmoy; Joshua, Jerry; Mahato, Nidhu

    2015-09-01

    This study was done to compare the changes in plantar load (weight distribution) and gait patterns before and after tibialis posterior transfer surgery in people affected by leprosy. Changes in gait patterns were observed and proportionate changes in plantar load were quantified using data captured by a baropodometer. All the eight patients who underwent tibialis posterior transfer surgery in 2013 in our hospital were included in the study. In addition to the regular pre-operative and post-operative assessments, the patients also underwent baropodometric evaluation. There was a significant change in plantar load at the heel, lateral border and forefoot. Using the foot pressure scan, it was noted that the progression of the centre of mass (displayed graphically as 'the gait line') was also affected by the altered pattern of weight distribution. This study reiterates the importance of tibialis posterior transfer because: it restores the normal gait pattern of 1, 2, 3 (where 1 is heel strike, 2 is mid foot contact and 3 is forefoot contact) and provides a more uniform distribution of planter load. PMID:26665356

  6. Correlation between balance and gait according to pelvic displacement in stroke patients

    PubMed Central

    Kong, Seon Woong; Jeong, Yeon Woo; Kim, Jin Young

    2015-01-01

    [Purpose] The purpose of this study was to investigate the correlations of balance and gait according to pelvic displacement in stroke patients. [Subjects] The subjects of this study were 58 stroke patients who had been admitted to a hospital. [Methods] A Global Postural System was used to measure pelvic displacement. To measure the balance ability, a Tetrax balance system was used to measure the weight distribution index and stability index. Gait ability was measured during the 10-Meter Walking Test and Figure-of-8 Walk Test. [Results] The results of this study showed that was significant positive correlation between the anterior superior iliac spine height difference in pelvic displacement and the weight distribution index and significant positive correlation between the posterior superior iliac spine height difference and the stability index in the normal position with the eyes closed. Statistically significant positive correlation also was found between the anterior superior iliac spine height difference and the straight and curved gait ability. [Conclusion] The increased pelvic displacement in stroke patients results in a decrease in balance ability and gait speed. This suggests that control of pelvic displacement is necessary before functional training for patients with stroke. PMID:26311948

  7. Reduction in bearing size due to superconductors in magnetic bearings

    NASA Technical Reports Server (NTRS)

    Rao, Dantam K.; Lewis, Paul; Dill, James F.

    1991-01-01

    A design concept that reduces the size of magnetic bearings is assessed. The small size will enable magnetic bearings to fit into limited available bearing volume of cryogenic machinery. The design concept, called SUPERC, uses (high Tc) superconductors or high-purity aluminum conductors in windings instead of copper. The relatively high-current density of these conductors reduces the slot radial thickness for windings, which reduces the size of the bearings. MTI developed a sizing program called SUPERC that translates the high-current density of these conductors into smaller sized bearings. This program was used to size a superconducting bearing to carry a 500 lb. load. The sizes of magnetic bearings needed by various design concepts are as follows: SUPERC design concept = 3.75 in.; magnet-bias design concept = 5.25 in.; and all electromagnet design concept = 7.0 in. These results indicate that the SUPERC design concept can significantly reduce the size of the bearing. This reduction, in turn, reduces the weight and yields a lighter bearing. Since the superconductors have inherently near-zero resistance, they are also expected to save power needed for operation considerably.

  8. Foot pressure analysis of adults with flat and normal feet at different gait speeds on an ascending slope

    PubMed Central

    Kim, Myoung-Kwon

    2015-01-01

    [Purpose] This study was conducted to determine the difference in foot pressures between flat and normal feet at different gait speeds on an ascending slope. [Subjects] This study enrolled 30 adults with normal (n=15) and flat feet (n=15), with ages from 21 to 30 years old, who had no history of neurological disorders or gait problems. A treadmill was used for the analysis of kinematic features during gait, using a slope of 10%, and gait velocities of slow, normal, and fast. [Methods] A foot pressure analyzer was used to measure changes in foot pressure. [Results] Compared to the normal subjects, the foot pressure of the flatfoot subjects showed a significant increase in the 2–3rd metatarsal region with increasing gait speed, whereas there were significant decreases in the 1st toe and 1st metatarsal regions with increasing gait speed. [Conclusion] The body weight of adults with flatfoot was concentrated on the 2–3rd metatarsal region during the stance phase and increased with walking speed on the ascending slope due to weakening of function of the medial longitudinal arch. PMID:26834348

  9. A Validated Smartphone-Based Assessment of Gait and Gait Variability in Parkinson’s Disease

    PubMed Central

    Ellis, Robert J.; Ng, Yee Sien; Zhu, Shenggao; Tan, Dawn M.; Anderson, Boyd; Schlaug, Gottfried; Wang, Ye

    2015-01-01

    Background A well-established connection exists between increased gait variability and greater fall likelihood in Parkinson’s disease (PD); however, a portable, validated means of quantifying gait variability (and testing the efficacy of any intervention) remains lacking. Furthermore, although rhythmic auditory cueing continues to receive attention as a promising gait therapy for PD, its widespread delivery remains bottlenecked. The present paper describes a smartphone-based mobile application (“SmartMOVE”) to address both needs. Methods The accuracy of smartphone-based gait analysis (utilizing the smartphone’s built-in tri-axial accelerometer and gyroscope to calculate successive step times and step lengths) was validated against two heel contact–based measurement devices: heel-mounted footswitch sensors (to capture step times) and an instrumented pressure sensor mat (to capture step lengths). 12 PD patients and 12 age-matched healthy controls walked along a 26-m path during self-paced and metronome-cued conditions, with all three devices recording simultaneously. Results Four outcome measures of gait and gait variability were calculated. Mixed-factorial analysis of variance revealed several instances in which between-group differences (e.g., increased gait variability in PD patients relative to healthy controls) yielded medium-to-large effect sizes (eta-squared values), and cueing-mediated changes (e.g., decreased gait variability when PD patients walked with auditory cues) yielded small-to-medium effect sizes—while at the same time, device-related measurement error yielded small-to-negligible effect sizes. Conclusion These findings highlight specific opportunities for smartphone-based gait analysis to serve as an alternative to conventional gait analysis methods (e.g., footswitch systems or sensor-embedded walkways), particularly when those methods are cost-prohibitive, cumbersome, or inconvenient. PMID:26517720

  10. Classification of Parkinson's Disease Gait Using Spatial-Temporal Gait Features.

    PubMed

    Wahid, Ferdous; Begg, Rezaul K; Hass, Chris J; Halgamuge, Saman; Ackland, David C

    2015-11-01

    Quantitative gait assessment is important in diagnosis and management of Parkinson's disease (PD); however, gait characteristics of a cohort are dispersed by patient physical properties including age, height, body mass, and gender, as well as walking speed, which may limit capacity to discern some pathological features. The aim of this study was twofold. First, to use a multiple regression normalization strategy that accounts for subject age, height, body mass, gender, and self-selected walking speed to identify differences in spatial-temporal gait features between PD patients and controls; and second, to evaluate the effectiveness of machine learning strategies in classifying PD gait after gait normalization. Spatial-temporal gait data during self-selected walking were obtained from 23 PD patients and 26 aged-matched controls. Data were normalized using standard dimensionless equations and multiple regression normalization. Machine learning strategies were then employed to classify PD gait using the raw gait data, data normalized using dimensionless equations, and data normalized using the multiple regression approach. After normalizing data using the dimensionless equations, only stride length, step length, and double support time were significantly different between PD patients and controls (p < 0.05); however, normalizing data using the multiple regression method revealed significant differences in stride length, cadence, stance time, and double support time. Random Forest resulted in a PD classification accuracy of 92.6% after normalizing gait data using the multiple regression approach, compared to 80.4% (support vector machine) and 86.2% (kernel Fisher discriminant) using raw data and data normalized using dimensionless equations, respectively. Our multiple regression normalization approach will assist in diagnosis and treatment of PD using spatial-temporal gait data. PMID:26551989

  11. Gait Initiation in Children with Rett Syndrome

    PubMed Central

    Isaias, Ioannis Ugo; Dipaola, Mariangela; Michi, Marlies; Marzegan, Alberto; Volkmann, Jens; Rodocanachi Roidi, Marina L.; Frigo, Carlo Albino; Cavallari, Paolo

    2014-01-01

    Rett syndrome is an X-linked neurodevelopmental condition mainly characterized by loss of spoken language and a regression of purposeful hand use, with the development of distinctive hand stereotypies, and gait abnormalities. Gait initiation is the transition from quiet stance to steady-state condition of walking. The associated motor program seems to be centrally mediated and includes preparatory adjustments prior to any apparent voluntary movement of the lower limbs. Anticipatory postural adjustments contribute to postural stability and to create the propulsive forces necessary to reach steady-state gait at a predefined velocity and may be indicative of the effectiveness of the feedforward control of gait. In this study, we examined anticipatory postural adjustments associated with gait initiation in eleven girls with Rett syndrome and ten healthy subjects. Muscle activity (tibialis anterior and soleus muscles), ground reaction forces and body kinematic were recorded. Children with Rett syndrome showed a distinctive impairment in temporal organization of all phases of the anticipatory postural adjustments. The lack of appropriate temporal scaling resulted in a diminished impulse to move forward, documented by an impairment in several parameters describing the efficiency of gait start: length and velocity of the first step, magnitude and orientation of centre of pressure-centre of mass vector at the instant of (swing-)toe off. These findings were related to an abnormal muscular activation pattern mainly characterized by a disruption of the synergistic activity of antagonistic pairs of postural muscles. This study showed that girls with Rett syndrome lack accurate tuning of feedforward control of gait. PMID:24743294

  12. Dynamic stability and phase resetting during biped gait

    NASA Astrophysics Data System (ADS)

    Nomura, Taishin; Kawa, Kazuyoshi; Suzuki, Yasuyuki; Nakanishi, Masao; Yamasaki, Taiga

    2009-06-01

    Dynamic stability during periodic biped gait in humans and in a humanoid robot is considered. Here gait systems of human neuromusculoskeletal system and a humanoid are simply modeled while keeping their mechanical properties plausible. We prescribe periodic gait trajectories in terms of joint angles of the models as a function of time. The equations of motion of the models are then constrained by one of the prescribed gait trajectories to obtain types of periodically forced nonlinear dynamical systems. Simulated gait of the models may or may not fall down during gait, since the constraints are made only for joint angles of limbs but not for the motion of the body trunk. The equations of motion can exhibit a limit cycle solution (or an oscillatory solution that can be considered as a limit cycle practically) for each selected gait trajectory, if an initial condition is set appropriately. We analyze the stability of the limit cycle in terms of Poincar maps and the basin of attraction of the limit cycle in order to examine how the stability depends on the prescribed trajectory. Moreover, the phase resetting of gait rhythm in response to external force perturbation is modeled. Since we always prescribe a gait trajectory in this study, reacting gait trajectories during the phase resetting are also prescribed. We show that an optimally prescribed reacting gait trajectory with an appropriate amount of the phase resetting can increase the gait stability. Neural mechanisms for generation and modulation of the gait trajectories are discussed.

  13. Modeling and simulation of normal and hemiparetic gait

    NASA Astrophysics Data System (ADS)

    Luengas, Lely A.; Camargo, Esperanza; Sanchez, Giovanni

    2015-09-01

    Gait is the collective term for the two types of bipedal locomotion, walking and running. This paper is focused on walking. The analysis of human gait is of interest to many different disciplines, including biomechanics, human-movement science, rehabilitation and medicine in general. Here we present a new model that is capable of reproducing the properties of walking, normal and pathological. The aim of this paper is to establish the biomechanical principles that underlie human walking by using Lagrange method. The constraint forces of Rayleigh dissipation function, through which to consider the effect on the tissues in the gait, are included. Depending on the value of the factor present in the Rayleigh dissipation function, both normal and pathological gait can be simulated. First of all, we apply it in the normal gait and then in the permanent hemiparetic gait. Anthropometric data of adult person are used by simulation, and it is possible to use anthropometric data for children but is necessary to consider existing table of anthropometric data. Validation of these models includes simulations of passive dynamic gait that walk on level ground. The dynamic walking approach provides a new perspective of gait analysis, focusing on the kinematics and kinetics of gait. There have been studies and simulations to show normal human gait, but few of them have focused on abnormal, especially hemiparetic gait. Quantitative comparisons of the model predictions with gait measurements show that the model can reproduce the significant characteristics of normal gait.

  14. Dynamic stability and phase resetting during biped gait.

    PubMed

    Nomura, Taishin; Kawa, Kazuyoshi; Suzuki, Yasuyuki; Nakanishi, Masao; Yamasaki, Taiga

    2009-06-01

    Dynamic stability during periodic biped gait in humans and in a humanoid robot is considered. Here gait systems of human neuromusculoskeletal system and a humanoid are simply modeled while keeping their mechanical properties plausible. We prescribe periodic gait trajectories in terms of joint angles of the models as a function of time. The equations of motion of the models are then constrained by one of the prescribed gait trajectories to obtain types of periodically forced nonlinear dynamical systems. Simulated gait of the models may or may not fall down during gait, since the constraints are made only for joint angles of limbs but not for the motion of the body trunk. The equations of motion can exhibit a limit cycle solution (or an oscillatory solution that can be considered as a limit cycle practically) for each selected gait trajectory, if an initial condition is set appropriately. We analyze the stability of the limit cycle in terms of Poincaré maps and the basin of attraction of the limit cycle in order to examine how the stability depends on the prescribed trajectory. Moreover, the phase resetting of gait rhythm in response to external force perturbation is modeled. Since we always prescribe a gait trajectory in this study, reacting gait trajectories during the phase resetting are also prescribed. We show that an optimally prescribed reacting gait trajectory with an appropriate amount of the phase resetting can increase the gait stability. Neural mechanisms for generation and modulation of the gait trajectories are discussed. PMID:19566263

  15. Gait synchronization in Caenorhabditis elegans

    PubMed Central

    Yuan, Jinzhou; Raizen, David M.; Bau, Haim H.

    2014-01-01

    Collective motion is observed in swarms of swimmers of various sizes, ranging from self-propelled nanoparticles to fish. The mechanisms that govern interactions among individuals are debated, and vary from one species to another. Although the interactions among relatively large animals, such as fish, are controlled by their nervous systems, the interactions among microorganisms, which lack nervous systems, are controlled through physical and chemical pathways. Little is known, however, regarding the mechanism of collective movements in microscopic organisms with nervous systems. To attempt to remedy this, we studied collective swimming behavior in the nematode Caenorhabditis elegans, a microorganism with a compact nervous system. We evaluated the contributions of hydrodynamic forces, contact forces, and mechanosensory input to the interactions among individuals. We devised an experiment to examine pair interactions as a function of the distance between the animals and observed that gait synchronization occurred only when the animals were in close proximity, independent of genes required for mechanosensation. Our measurements and simulations indicate that steric hindrance is the dominant factor responsible for motion synchronization in C. elegans, and that hydrodynamic interactions and genotype do not play a significant role. We infer that a similar mechanism may apply to other microscopic swimming organisms and self-propelled particles. PMID:24778261

  16. SURGICAL CORRECTION OF BILATERAL PATELLAR LUXATION IN AN AMERICAN BLACK BEAR CUB (URSUS AMERICANUS).

    PubMed

    Bennett, Katarina R; Desmarchelier, Marion R; Bailey, Trina R

    2015-06-01

    A wild orphaned male American black bear cub ( Ursus americanus ) presented with hind limb gait abnormalities and was found to have bilateral grade 3 laterally luxating patellas. There were no other significant abnormalities detected on neurologic, radiographic, or hematologic examinations. The trochlear grooves were deepened with a chondroplasty, and the redundant soft tissues imbricated. There was a marked improvement in the bear's gait postoperatively, with an apparent full return to function. To the authors' knowledge, patellar luxation has not been reported in the Ursidae family, and the success in this case suggests that this technique may be used in large wild or captive carnivore cubs. PMID:26056894

  17. Scrunching: a novel escape gait in planarians.

    PubMed

    Cochet-Escartin, Olivier; Mickolajczyk, Keith J; Collins, Eva-Maria S

    2015-10-01

    The ability to escape a predator or other life-threatening situations is central to animal survival. Different species have evolved unique strategies under anatomical and environmental constraints. In this study, we describe a novel musculature-driven escape gait in planarians, 'scrunching', which is quantitatively different from other planarian gaits, such as gliding and peristalsis. We show that scrunching is a conserved gait among different flatworm species, underlying its importance as an escape mechanism. We further demonstrate that it can be induced by a variety of physical stimuli, including amputation, high temperature, electric shock and low pH. We discuss the functional basis for scrunching as the preferential gait when gliding is impaired due to a disruption of mucus production. Finally, we show that the key mechanical features of scrunching are adequately captured by a simple biomechanical model that is solely based on experimental data from traction force microscopy and tissue rheology without fit parameters. Together, our results form a complete description of this novel form of planarian locomotion. Because scrunching has distinct dynamics, this gait can serve as a robust behavioral readout for studies of motor neuron and muscular functions in planarians and in particular the restoration of these functions during regeneration. PMID:26356147

  18. Scrunching: a novel escape gait in planarians

    NASA Astrophysics Data System (ADS)

    Cochet-Escartin, Olivier; Mickolajczyk, Keith J.; Collins, Eva-Maria S.

    2015-10-01

    The ability to escape a predator or other life-threatening situations is central to animal survival. Different species have evolved unique strategies under anatomical and environmental constraints. In this study, we describe a novel musculature-driven escape gait in planarians, ‘scrunching’, which is quantitatively different from other planarian gaits, such as gliding and peristalsis. We show that scrunching is a conserved gait among different flatworm species, underlying its importance as an escape mechanism. We further demonstrate that it can be induced by a variety of physical stimuli, including amputation, high temperature, electric shock and low pH. We discuss the functional basis for scrunching as the preferential gait when gliding is impaired due to a disruption of mucus production. Finally, we show that the key mechanical features of scrunching are adequately captured by a simple biomechanical model that is solely based on experimental data from traction force microscopy and tissue rheology without fit parameters. Together, our results form a complete description of this novel form of planarian locomotion. Because scrunching has distinct dynamics, this gait can serve as a robust behavioral readout for studies of motor neuron and muscular functions in planarians and in particular the restoration of these functions during regeneration.

  19. Quantitative evaluation of gait ataxia by accelerometers.

    PubMed

    Shirai, Shinichi; Yabe, Ichiro; Matsushima, Masaaki; Ito, Yoichi M; Yoneyama, Mitsuru; Sasaki, Hidenao

    2015-11-15

    An appropriate biomarker for spinocerebellar degeneration (SCD) has not been identified. Here, we performed gait analysis on patients with pure cerebellar type SCD and assessed whether the obtained data could be used as a neurophysiological biomarker for cerebellar ataxia. We analyzed 25 SCD patients, 25 patients with Parkinson's disease as a disease control, and 25 healthy control individuals. Acceleration signals during 6 min of walking and 1 min of standing were measured by two sets of triaxial accelerometers that were secured with a fixation vest to the middle of the lower and upper back of each subject. We extracted two gait parameters, the average and the coefficient of variation of motion trajectory amplitude, from each acceleration component. Then, each component was analyzed by correlation with the Scale for the Assessment and Rating of Ataxia (SARA) and the Berg Balance Scale (BBS). Compared with the gait control of healthy subjects and concerning correlation with severity and disease specificity, our results suggest that the average amplitude of medial-lateral (upper back) of straight gait is a physiological biomarker for cerebellar ataxia. Our results suggest that gait analysis is a quantitative and concise evaluation scale for the severity of cerebellar ataxia. PMID:26362336

  20. Recognition of affect based on gait patterns.

    PubMed

    Karg, Michelle; Kühnlenz, Kolja; Buss, Martin

    2010-08-01

    To provide a means for recognition of affect from a distance, this paper analyzes the capability of gait to reveal a person's affective state. We address interindividual versus person-dependent recognition, recognition based on discrete affective states versus recognition based on affective dimensions, and efficient feature extraction with respect to affect. Principal component analysis (PCA), kernel PCA, linear discriminant analysis, and general discriminant analysis are compared to either reduce temporal information in gait or extract relevant features for classification. Although expression of affect in gait is covered by the primary task of locomotion, person-dependent recognition of motion capture data reaches 95% accuracy based on the observation of a single stride. In particular, different levels of arousal and dominance are suitable for being recognized in gait. It is concluded that gait can be used as an additional modality for the recognition of affect. Application scenarios include monitoring in high-security areas, human-robot interaction, and cognitive home environments. PMID:20350859

  1. Development and Decline of Upright Gait Stability

    PubMed Central

    Iosa, Marco; Fusco, Augusto; Morone, Giovanni; Paolucci, Stefano

    2014-01-01

    Upright gait is a peculiar characteristic of humans that requires the ability to manage upper body dynamic balance while walking, despite the perturbations that are generated by movements of the lower limbs. Most of the studies on upright gait stability have compared young adults and the elderly to determine the effects of aging. In other studies, the comparison was between healthy subjects and patients to examine specific pathologies. Fewer researches have also investigated the development of upright gait stability in children. This review discusses these studies in order to provide an overview of this relevant aspect of human locomotion. A clear trend from development to decline of upright gait stability has been depicted across the entire lifespan, from toddlers at first steps to elderly. In old individuals, even if healthy, the deterioration of skeletal muscle, combined with sensorial and cognitive performance, reduces the ability to maintain an upright trunk during walking, increasing the instability and the risk of falls. Further, the pathological causes of altered development or of a sudden loss of gait stability, as well as the environmental influence are investigated. The last part of this review is focused on the control of upper body accelerations during walking, a particularly interesting topic for the recent development of low-cost wearable accelerometers. PMID:24550829

  2. Sporadic hyperekplexia presenting with an ataxic gait.

    PubMed

    Rouco, Idoia; Bilbao, Iker; Losada, Jose; Maestro, Iratxe; Zarranz, Juan Jose

    2014-02-01

    We describe a 62-year-old man with a sporadic form of hyperekplexia who presented with an unsteady gait, present since the age of 47. His clinical examination revealed an insecure broad-based gait and difficulty with tandem walking but no other abnormalities. For nearly a decade the patient was misdiagnosed with an idiopathic ataxia. A video electroencephalogram combined with an electromyogram during sudden auditory stimulus demonstrated an excessive startle response. An extensive work-up ruled out all the known causes of symptomatic hyperekplexia including anti-glycine receptor antibodies. Treatment with clonazepam markedly reduced the threshold and intensity of the startle response, enabling him to recover independence. Hyperekplexia is frequently associated with an awkward and hesitating gait, but these gait abnormalities might be confused with other causes of gait disorders if one is not aware of this disease. We report this patient to highlight that a correct diagnosis of hyperekplexia is crucial, because its treatment may change quality of life. PMID:24054400

  3. Gait stability in children with cerebral palsy

    PubMed Central

    Bruijn, Sjoerd M.; Millard, Matthew; van Gestel, Leen; Meyns, Pieter; Jonkers, Ilse; Desloovere, Kaat

    2013-01-01

    Children with unilateral Cerebral Palsy (CP) have several gait impairments, amongst which impaired gait stability may be one. We tested whether a newly developed stability measure (the foot placement estimator, FPE) which does not require long data series, can be used to asses gait stability in typically developing (TD) children as well as children with CP. In doing so, we tested the FPE’s sensitivity to the assumptions needed to calculate this measure, as well as the ability of the FPE to detect differences in stability between children with CP and TD children, and differences in walking speed. Participants were asked to walk at two different speeds, while gait kinematics were recorded. From these data, the FPE, as well as the error that violations of assumptions of the FPE could have caused were calculated. The results showed that children with CP walked with marked instabilities in anterior-posterior and mediolateral directions. Furthermore, errors caused by violations of assumptions in calculation of FPE were only small (~1.5 cm), while effects of walking speed (~20 cm per m/s increase in walking speed) and group (~5cm) were much larger. These results suggest that the FPE may be used to quantify gait stability in TD children and children with CP. PMID:23500163

  4. Lubrication for high load duplex bearings

    SciTech Connect

    Steinhoff, R.G.

    1997-08-01

    Three ES and H-compatible lubricants (Environment, Safety and Health) for high load duplex bearing applications were evaluated and compared against trichlorotrifluoroethane (Freon) deposition of low molecular weight polytetrafluoroethylene (PTFE) bearing lubricant extracted from Vydax{trademark}. Vydax is a product manufactured by DuPont consisting of various molecular weights of PTFE suspended in trichlorotrifluoroethane (Freon) which is an ozone-depleting solvent. Bearings with Supercritical CO{sub 2} deposition of PTFE extracted from Vydax AR/IPA, bearings with titanium carbide coated balls, and bearings with diamond-like carbon races and retainers were evaluated. Bearings with Supercritical CO{sub 2} deposition of PTFE from Vydax AR/IPA performed as well as bearings with Freon deposition of PTFE from Freon-based Vydax.

  5. Black Bear

    The Oklahoma Unit has been studying population expansion and genetics of black bear in southeastern Oklahoma since 2001. Live capture and hair snares have been used to collect samples; from left to right: field technician, JD Davis and M.S. candidates, Angie Brown and Meredith Magnuson....

  6. ZeroG: overground gait and balance training system.

    PubMed

    Hidler, Joseph; Brennan, David; Black, Iian; Nichols, Diane; Brady, Kathy; Nef, Tobias

    2011-01-01

    A new overground body-weight support system called ZeroG has been developed that allows patients with severe gait impairments to practice gait and balance activities in a safe, controlled manner. The unloading system is capable of providing up to 300 lb of static support and 150 lb of dynamic (or constant force) support using a custom-series elastic actuator. The unloading system is mounted to a driven trolley, which rides along an overhead rail. We evaluated the performance of ZeroG's unloading system, as well as the trolley tracking system, using benchtop and human-subject testing. Average root-mean-square and peak errors in unloading were 2.2 and 7.2 percent, respectively, over the range of forces tested while trolley tracking errors were less than 3 degrees, indicating the system was able to maintain its position above the subject. We believe training with ZeroG will allow patients to practice activities that are critical to achieving functional independence at home and in the community. PMID:21674384

  7. Metatarsal Loading During Gait-A Musculoskeletal Analysis.

    PubMed

    Al-Munajjed, Amir A; Bischoff, Jeffrey E; Dharia, Mehul A; Telfer, Scott; Woodburn, James; Carbes, Sylvain

    2016-03-01

    Detailed knowledge of the loading conditions within the human body is essential for the development and optimization of treatments for disorders and injuries of the musculoskeletal system. While loads in the major joints of the lower limb have been the subject of extensive study, relatively little is known about the forces applied to the individual bones of the foot. The objective of this study was to use a detailed musculoskeletal model to compute the loads applied to the metatarsal bones during gait across several healthy subjects. Motion-captured gait trials and computed tomography (CT) foot scans from four healthy subjects were used as the inputs to inverse dynamic simulations that allowed the computation of loads at the metatarsal joints. Low loads in the metatarsophalangeal (MTP) joint were predicted before terminal stance, however, increased to an average peak of 1.9 times body weight (BW) before toe-off in the first metatarsal. At the first tarsometatarsal (TMT) joint, loads of up to 1.0 times BW were seen during the early part of stance, reflecting tension in the ligaments and muscles. These loads subsequently increased to an average peak of 3.0 times BW. Loads in the first ray were higher compared to rays 2-5. The joints were primarily loaded in the longitudinal direction of the bone. PMID:26719905

  8. Human Odometry Verifies the Symmetry Perspective on Bipedal Gaits

    ERIC Educational Resources Information Center

    Turvey, M. T.; Harrison, Steven J.; Frank, Till D.; Carello, Claudia

    2012-01-01

    Bipedal gaits have been classified on the basis of the group symmetry of the minimal network of identical differential equations (alias "cells") required to model them. Primary gaits are characterized by dihedral symmetry, whereas secondary gaits are characterized by a lower, cyclic symmetry. This fact was used in a test of human odometry. Results…

  9. Human gait recognition based on compactness

    NASA Astrophysics Data System (ADS)

    Chen, Feng; Jiang, Jie; Zhang, Guangjun

    2008-10-01

    Gait recognition is new biological identity technology and widely researched in recent years for its many advantages compared with other biological identity technology. In this paper, we propose a simple but effective feature-compactness for gait recognition. First an improved background subtraction algorithm is used to obtain the silhouettes. Then the compactness is extracted from the images in the gait sequence as the feature vector. In the step of classification, DTW algorithm is adopted to adjust the feature vectors before classifying and two classifiers (NN and ENN) are used as classifiers. Because of the simple features which we choose, it consumes little time for recognition and the results turn out to be encouraging.

  10. Virtual gait training for children with cerebral palsy using the Lokomat gait orthosis.

    PubMed

    Koenig, Alexander; Wellner, Mathias; Köneke, Susan; Meyer-Heim, Andreas; Lünenburger, Lars; Riener, Robert

    2008-01-01

    The Lokomat gait orthosis was developed in the Spinal Cord Injury Center at the University Hospital Balgrist Zurich and provides automatic gait training for patients with neurological gait impairments, such as Cerebral Palsy (CP). Each patient undergoes a task-oriented Lokomat rehabilitation training program via a virtual reality setup. In four virtual scenarios, the patient is able to exercise tasks such as wading through water, playing soccer, overstepping obstacles or training in a street scenario, each task offering varying levels of difficulty. Patients provided positive feedback in reference to the utilized haptic method, specifically addressing the sufficient degree of realism. In a single case study, we verified the task difficulty. PMID:18391287

  11. The trajectory of gait speed preceding MCI

    PubMed Central

    Buracchio, Teresa; Dodge, Hiroko; Howieson, Diane; Wasserman, Dara; Kaye, Jeffrey

    2010-01-01

    Objectives To compare the trajectory of motor decline, as measured by gait speed and finger tapping speed, between those who developed mild cognitive impairment (MCI) and those who remained cognitively intact. We also sought to determine the approximate time at which decline in motor function accelerated in those who developed MCI. Design Longitudinal cohort study Participants Subjects were 204 healthy seniors (58% women) from the Oregon Brain Aging Study evaluated for up to 20 years with annual neurologic, neuropsychological and motor examinations. Main Outcome Measures The pattern of motor decline with aging was compared using a mixed-effects model with an interaction term for age and clinical diagnosis of mild cognitive impairment. The time prior to diagnosis of MCI when the change in gait or tapping speed accelerates was assessed with a mixed-effects model with a change point for men and women, separately and combined, who developed MCI. Results The rates of change with aging of gait speed (p<0.001) and tapping speed in the dominant hand (p<0.003) and non-dominant hand (p<0.001) were significantly different between MCI converters and non-converters. Using a change-point analysis for MCI converters, the decrease in gait speed accelerated by 0.02 m/s/yr (p<0.001) occurring 12.1 years prior to the onset of MCI. An acceleration of gait speed decline occurred earlier in men than women. For tapping speed, the change point occurred after the onset of MCI for both dominant and non-dominant hands when men and women were combined. Conclusions Motor decline as indexed by gait speed accelerates up to 12 years prior to MCI. Longitudinal changes in motor function may be useful in the early detection of dementia during pre-clinical stages when the utility of disease-modifying therapies would be greatest. PMID:20697049

  12. Motor imagery of gait: a quantitative approach.

    PubMed

    Bakker, M; de Lange, F P; Stevens, J A; Toni, I; Bloem, B R

    2007-05-01

    Motor imagery (MI) is widely used to study cognitive aspects of the neural control of action. Prior studies were mostly centred on hand and arm movements. Recently a few studies have used imagery tasks to explore the neurophysiology of human gait, but it remains unclear how to ascertain whether subjects actually perform imagery of gait as requested. Here we describe a new experimental protocol to quantify imagery of gait, by behaviourally distinguishing it from visual imagery (VI) processes and by showing its temporal correspondence with actual gait. Fourteen young healthy subjects performed two imagery tasks and an actual walking (AW) task. During both imagery tasks subjects were sitting on a chair and faced a computer screen that presented photographs of walking trajectories. During one task (MI), subjects had to imagine walking along the walking trajectory. During the other task (VI), subjects had to imagine seeing a disc moving along the walking trajectory. During the AW task, subjects had to physically walk along the same walking trajectory as presented on the photographs during the imagery tasks. We manipulated movement distance by changing the length of the walking trajectory, and movement difficulty by changing the width of the walking trajectory. Subjects reported onset and offset of both actual and imagined movements with a button press. The time between the two button presses was taken as the imagined or actual movement time (MT). MT increased with increasing path length and decreasing path width in all three tasks. Crucially, the effect of path width on MT was significantly stronger during MI and AW than during VI. The results demonstrate a high temporal correspondence between imagined and AW, suggesting that MI taps into similar cerebral resources as those used during actual gait. These results open the possibility of using this protocol for exploring neurophysiological correlates of gait control in humans. PMID:17211663

  13. Footwear Decreases Gait Asymmetry during Running

    PubMed Central

    Hoerzer, Stefan; Federolf, Peter A.; Maurer, Christian; Baltich, Jennifer; Nigg, Benno M.

    2015-01-01

    Previous research on elderly people has suggested that footwear may improve neuromuscular control of motion. If footwear does in fact improve neuromuscular control, then such an influence might already be present in young, healthy adults. A feature that is often used to assess neuromuscular control of motion is the level of gait asymmetry. The objectives of the study were (a) to develop a comprehensive asymmetry index (CAI) that is capable of detecting gait asymmetry changes caused by external boundary conditions such as footwear, and (b) to use the CAI to investigate whether footwear influences gait asymmetry during running in a healthy, young cohort. Kinematic and kinetic data were collected for both legs of 15 subjects performing five barefoot and five shod over-ground running trials. Thirty continuous gait variables including ground reaction forces and variables of the hip, knee, and ankle joints were computed for each leg. For each individual, the differences between the variables for the right and left leg were calculated. Using this data, a principal component analysis was conducted to obtain the CAI. This study had two main outcomes. First, a sensitivity analysis suggested that the CAI had an improved sensitivity for detecting changes in gait asymmetry caused by external boundary conditions. The CAI may, therefore, have important clinical applications such as monitoring the progress of neuromuscular diseases (e.g. stroke or cerebral palsy). Second, the mean CAI for shod running (131.2 ± 48.5; mean ± standard deviation) was significantly lower (p = 0.041) than the CAI for barefoot running (155.7 ± 39.5). This finding suggests that in healthy, young adults gait asymmetry is reduced when running in shoes compared to running barefoot, which may be a result of improved neuromuscular control caused by changes in the afferent sensory feedback. PMID:26488484

  14. The load applied to the foot in a patellar ligament-bearing cast.

    PubMed

    Aita, D; Bhave, A; Herzenberg, J E; Paley, D; Cannada, L

    1998-11-01

    The purpose of this study was to determine whether a patellar ligament-bearing cast reduces the load applied to a foot in a cast. In a study of ten people who had no history of gait abnormalities, disease involving the motor system, or deformities of the lower extremities, we compared the load applied to the plantar aspect of a foot in a cast (as detected with F-Scan computer-monitored pedobarographic sensors) with the total load that an extremity in a cast receives relative to the ground (as detected with force-plates). Six trials were completed three times by each person. The trials consisted of walking (1) while wearing regular shoes; (2) with a patellar ligament-bearing cast on one leg; (3) with a patellar ligament-bearing cast and an overlying soft knee brace, locked in full extension, on the leg; (4) with only a below-the-knee cast on the leg; (5) with a below-the-knee cast and an overlying knee brace, locked in full extension, on the leg; and (6) with only a knee brace, locked in full extension, on the leg. The loads at peak heel-strike for all three trials were averaged and normalized to body weight. The load on the plantar aspect of the foot, as compared with the total load, was reduced a mean of 11 percent when the patellar ligament-bearing cast was worn alone, and it was reduced a mean of 26 percent when the patellar ligament-bearing cast was used with an overlying knee brace locked in full extension. This difference was significant (p = 0.007). With the numbers available, we could not detect a significant difference between the reduction in load when a patellar ligament-bearing cast was worn alone compared with that when a below-the-knee cast was worn alone or between the reduction when a below-the-knee cast was worn alone compared with that when a below-the-knee cast was used with a knee brace (p = 0.3). In conclusion, we could not demonstrate a significant reduction in the load on the foot when a patellar ligament-bearing cast was used in a traditional fashion; however, a significant (p = 0.007) reduction in load was found when a knee brace locked in full extension was worn in addition to the patellar ligament-bearing cast. PMID:9840627

  15. Periodic gaits for the CMU ambler

    NASA Technical Reports Server (NTRS)

    Mahalingam, Swaminathan; Dwivedi, Suren N.

    1989-01-01

    The configuration of the Carnegie Mellon University Ambler, a six legged autonomous walking vehicle for exploring Mars, enables the recovery of a trailing leg past the leading leg to reduce the energy expenditure in terrain interactions. Gaits developed for this unprecedented configuration are described. A stability criterion was developed which ensures stability of the vehicle in the event of failure of any one of the supporting legs. Periodic gaits developed for the Ambler utilize the Ambler's unique abilities, and continuously satisfy the stability criterion.

  16. Acoustically-observable properties of adult gait.

    PubMed

    Bradley, Marshall; Sabatier, James M

    2012-03-01

    An approach has been developed for extracting human gait parameters from micro Doppler sonar grams. Key parameters include average speed of walking, torso velocity, walk cycle time, and peak leg velocity. The approach is a modification of a technique previously used in radar data analysis. It has been adapted because of differences between sonar and radar micro Doppler grams. The approach has been applied to an acoustic data set of 16 female and 60 male walkers. Statistics have been tabulated that illustrate the similarities and dissimilarities between female and male gait. Males tend to walk with larger walk cycle times and peak leg velocities than females. PMID:22423810

  17. Gait recognition based on fusion features

    NASA Astrophysics Data System (ADS)

    Wu, Haizhen; Jiang, Jiafu; Chen, Xi

    2009-10-01

    Gait recognition and analysis is a promising biometrics technology finding applications in numerous sectors of our society. This paper proposes a new fusion algorithm where the static and dynamic features are fused to obtain optimal performance. The new fusion algorithm divides decision situations into two categories. The wavelet moment is used to describe the static features of gait sequence images, and the three widths of the body contour are used to describe the dynamic features. In addition, the Principal Component Analysis (PCA) for feature transformation of spatial templates is proposed. The experimental results demonstrate that the proposed algorithm performs an encouraging recognition rate.

  18. Predictive simulation of gait in rehabilitation.

    PubMed

    Ackermann, Marko; van den Bogert, Antonie J

    2010-01-01

    This paper aims at demonstrating the capabilities of predictive, computational simulations of gait in clinical applications. In particular, the gait with bilateral and unilateral Ankle Foot-Orthoses (AFO's) is investigated. The problem is formulated in an optimal control framework where optimal motion and neural excitations to the muscles are computed solely on the basis of an assumed optimality criterion and periodicity constraints. The enormous potential of the approach as well as some of the current limitations are discussed on the light of simulation results. PMID:21096280

  19. A stochastic model of human gait dynamics

    NASA Astrophysics Data System (ADS)

    Ashkenazy, Yosef; M. Hausdorff, Jeffrey; Ch. Ivanov, Plamen; Eugene Stanley, H.

    2002-12-01

    We present a stochastic model of gait rhythm dynamics, based on transitions between different “neural centers”, that reproduces distinctive statistical properties of normal human walking. By tuning one model parameter, the transition (hopping) range, the model can describe alterations in gait dynamics from childhood to adulthood-including a decrease in the correlation and volatility exponents with maturation. The model also generates time series with multifractal spectra whose broadness depends only on this parameter. Moreover, we find that the volatility exponent increases monotonically as a function of the width of the multifractal spectrum, suggesting the possibility of a change in multifractality with maturation.

  20. MRI of Weight-bearing and Movement

    PubMed Central

    Shapiro, Lauren M.; Gold, Garry E.

    2011-01-01

    Conventional, static magnetic resonance imaging (MRI) is able to provide a vast amount of information regarding the anatomy and pathology of the musculoskeletal system. However, patients, especially those whose pain is position dependent or elucidated by movement, may benefit from more advanced imaging techniques that allow for the acquisition of functional information. This manuscript reviews a variety of advancements in magnetic resonance imaging techniques that are used to image the musculoskeletal system dynamically, while in motion or under load. The methodologies, advantages and drawbacks of Stress MRI, Cine PC MRI and Real-Time MRI are discussed as each has helped to advance the field by providing a scientific basis for understanding normal and pathological musculoskeletal anatomy and function. Advancements in dynamic MR imaging will certainly lead to improvements in the understanding, prevention, diagnosis and treatment of musculoskeletal disorders. It is difficult to anticipate that dynamic MRI will replace conventional MRI, however, dynamic MRI may provide additional valuable information to findings of conventional MRI. PMID:22138286

  1. The relationship between 2D static features and 2D dynamic features used in gait recognition

    NASA Astrophysics Data System (ADS)

    Alawar, Hamad M.; Ugail, Hassan; Kamala, Mumtaz; Connah, David

    2013-05-01

    In most gait recognition techniques, both static and dynamic features are used to define a subject's gait signature. In this study, the existence of a relationship between static and dynamic features was investigated. The correlation coefficient was used to analyse the relationship between the features extracted from the "University of Bradford Multi-Modal Gait Database". This study includes two dimensional dynamic and static features from 19 subjects. The dynamic features were compromised of Phase-Weighted Magnitudes driven by a Fourier Transform of the temporal rotational data of a subject's joints (knee, thigh, shoulder, and elbow). The results concluded that there are eleven pairs of features that are considered significantly correlated with (p<0.05). This result indicates the existence of a statistical relationship between static and dynamics features, which challenges the results of several similar studies. These results bare great potential for further research into the area, and would potentially contribute to the creation of a gait signature using latent data.

  2. An investigation of gait in children with Attention Deficit Hyperactivity Disorder: a case controlled study.

    PubMed

    Papadopoulos, Nicole; McGinley, Jennifer L; Bradshaw, John L; Rinehart, Nicole J

    2014-08-30

    This study aimed to compare the gait of children with ADHD - Combined Type (ADHD-CT) to typically developing (TD) children. Children with ADHD-CT (n=14; mean age 10 years 4 months) and a TD group (n=13; mean age 10 years 9 months) walked at self-selected slow, preferred and fast speed on an electronic walkway system. Participants completed a total of 15 walking trials; 5 trials per walking condition. Groups were matched on age, intellectual functioning, height and weight. In the preferred walking condition, there was no difference in spatio-temporal gait variables between the ADHD-CT and TD control groups. At self-selected fast speed, children with ADHD-CT were faster and walked with a higher cadence. The subtle alterations in gait pattern that may reflect a timing deficit is consistent with previous ADHD motor studies. In addition, this study extends previous studies in characterising the unique gait profile of non-medicated children with ADHD-CT where a diagnosis of autism spectrum disorder has been ruled out. PMID:24837426

  3. CUSHIONED BEARING

    DOEpatents

    Rushing, F.C.

    1960-09-01

    A vibration damping device effective to dampen vibrations occurring at the several critical speeds encountered in the operation of a high-speed centrifuge is described. A self-centering bearing mechanism is used to protect both the centrifuge shaft and the damping mechanism. The damping mechanism comprises spaced-apant, movable, and stationary sleeve members arranged concentrically of a rotating shaft with a fluid maintained between the members. The movable sleeve member is connected to the shaft for radial movement therewith.

  4. Fluctuation and synchronization of gait intervals and gait force profiles distinguish stages of Parkinson's disease

    NASA Astrophysics Data System (ADS)

    Bartsch, Ronny; Plotnik, Meir; Kantelhardt, Jan W.; Havlin, Shlomo; Giladi, Nir; Hausdorff, Jeffrey M.

    2007-09-01

    We study the effects of Parkinson's disease (PD) on the long-term fluctuation and phase synchronization properties of gait timing (series of interstride intervals) as well as gait force profiles (series characterizing the morphological changes between the steps). We find that the fluctuations in the gait timing are significantly larger for PD patients and early PD patients, who were not treated yet with medication, compared to age-matched healthy controls. Simultaneously, the long-term correlations and the phase synchronization of right and left leg are significantly reduced in both types of PD patients. Surprisingly, long-term correlations of the gait force profiles are relatively weak for treated PD patients and healthy controls, while they are significantly larger for early PD patients. The results support the idea that timing and morphology of recordings obtained from a complex system can contain complementary information.

  5. Gait identification from invisible shadows

    NASA Astrophysics Data System (ADS)

    Iwashita, Yumi; Uchino, Koji; Kurazume, Ryo; Stoica, Adrian

    2012-06-01

    This paper introduces a person identification system that uses as input the shadow images of a walking person, as projected by multiple lights(in this application invisible/infrared lights); the system uses a database of examples of shadows images of a number of people who walk. While it is accepted that personal identification has a higher correct classification rate if views from multiple cameras are used, most systems use only one camera, mainly because (i) Installation in real-world environments is easier, less cameras and no need to synchronize cameras, (ii) Computational cost is reduced. In the proposed system, we obtain the advantages of multiple viewpoints with a single camera and additional light sources. More specific, we install multiple infrared lights to project shadows of a subject on the ground and a camera with an infrared transmitting filter mounted in the ceiling inside of a building. Shadow areas, which are projections of one's body on the ground by multiple lights, can be considered as body areas captured from different viewpoints; thus, the proposed system is able to capture multiple projections of the body from a single camera. We explored in other papers the use of sunproduced shadow for identification of people walking freely in the outdoor. In this paper the application scenario is a system installed at the airport in the areas that precedes the immigration checkpoint. Japan already has health monitoring cameras focused on approaching individuals, to determine their health condition; the here described system would also be installed in such a controlled area with restricted walk corridors of walk and controlled lighting. Gait is a remote biometrics and can provide early warning; on another hand it can be used as corroborating evidence in a multi-modal biometrics system. A database of images including shadows for a set of 28 walking people was collected, and the features extracted from shadow areas by affine moment invariants, after which identification of the subject followed. The experiments using the database show the effectiveness of the proposed method and further prove the superiority of using multiple viewpoints compared to a single viewpoint.

  6. Tooling Converts Stock Bearings To Custom Bearings

    NASA Technical Reports Server (NTRS)

    Fleenor, E. N., Jr.

    1983-01-01

    Technique for reworking stock bearings saves time and produces helicopter-rotor bearings ground more precisely. Split tapered ring at one end of threaded bolt expands to hold inside of inner race bearing assembly; nut, at other end of bolt, adjusts amount of spring tension. Piece of hardware grasps bearing firmly without interfering with grinding operation. Operation produces bearing of higher quality than commercially available bearings.

  7. Basic gait analysis based on continuous wave radar.

    PubMed

    Zhang, Jun

    2012-09-01

    A gait analysis method based on continuous wave (CW) radar is proposed in this paper. Time-frequency analysis is used to analyze the radar micro-Doppler echo from walking humans, and the relationships between the time-frequency spectrogram and human biological gait are discussed. The methods for extracting the gait parameters from the spectrogram are studied in depth and experiments on more than twenty subjects have been performed to acquire the radar gait data. The gait parameters are calculated and compared. The gait difference between men and women are presented based on the experimental data and extracted features. Gait analysis based on CW radar will provide a new method for clinical diagnosis and therapy. PMID:22951210

  8. Gait-Based Human Identification Using Appearance Matching

    NASA Astrophysics Data System (ADS)

    Kale, A.; Cuntoor, N.; Yegnanarayana, B.; Rajagopalan, A. N.; Chellappa, R.

    In this chapter, we present an appearance-based approach for recognizing human gait. Given the gait video of an individual, the images are binarized and the width of the outer contour of the silhouette of that individual is obtained for each image frame. Several gait features are derived from this basic width vector. Temporally ordered sequences of the feature vectors are then used to represent the gait of a person. While matching the feature templates for recognition, dynamic time-warping (DTW), which is a nonlinear time-normalization technique, is used to deal with naturally occurring changes in the walking speeds of individuals. The performance of the proposed method is tested on indoor as well as outdoor gait databases, and the efficacy of different gait features and their noise resilience is studied. The experiments also demonstrate the effect of change in the viewing angle and frame rate of data capture on the accuracy of gait recognition.

  9. Neuroimaging as a window into gait disturbances and freezing of gait in patients with Parkinson's disease.

    PubMed

    Herman, Talia; Giladi, Nir; Hausdorff, Jeffrey M

    2013-12-01

    Neuroimaging has been applied to better understand the neural mechanisms underlying gait disturbances in Parkinson's disease (PD). In the present paper, we review studies that used neuroimaging methods to investigate mobility, walking and freezing of gait (FOG) in PD, focusing on the recent literature. Examination of these studies suggests that gait changes in PD are due to widespread alterations in the structure and function of the brain that go beyond the basal ganglia. For example, cortical structures including the frontal and parietal lobes, the mesencephalic locomotor region and specifically, the pedunculopontine nucleus, all apparently play important roles in the control of gait in PD. Nonetheless, there are some significant inconsistencies across the different studies and many questions remain regarding the precise pathological processes that contribute to gait disturbances, in general, and to FOG, more specifically. A discussion of new insights into the neural mechanisms underlying gait disturbances are presented along with a summary of the disadvantages and limitations of the existing techniques and suggestions for future directions. PMID:24136458

  10. Multilayer Joint Gait-Pose Manifolds for Human Gait Motion Modeling.

    PubMed

    Ding, Meng; Fan, Guolian

    2015-11-01

    We present new multilayer joint gait-pose manifolds (multilayer JGPMs) for complex human gait motion modeling, where three latent variables are defined jointly in a low-dimensional manifold to represent a variety of body configurations. Specifically, the pose variable (along the pose manifold) denotes a specific stage in a walking cycle; the gait variable (along the gait manifold) represents different walking styles; and the linear scale variable characterizes the maximum stride in a walking cycle. We discuss two kinds of topological priors for coupling the pose and gait manifolds, i.e., cylindrical and toroidal, to examine their effectiveness and suitability for motion modeling. We resort to a topologically-constrained Gaussian process (GP) latent variable model to learn the multilayer JGPMs where two new techniques are introduced to facilitate model learning under limited training data. First is training data diversification that creates a set of simulated motion data with different strides. Second is the topology-aware local learning to speed up model learning by taking advantage of the local topological structure. The experimental results on the Carnegie Mellon University motion capture data demonstrate the advantages of our proposed multilayer models over several existing GP-based motion models in terms of the overall performance of human gait motion modeling. PMID:25532201

  11. Gait recognition based on Kinect sensor

    NASA Astrophysics Data System (ADS)

    Ahmed, Mohammed; Al-Jawad, Naseer; Sabir, Azhin T.

    2014-05-01

    This paper presents gait recognition based on human skeleton and trajectory of joint points captured by Microsoft Kinect sensor. In this paper Two sets of dynamic features are extracted during one gait cycle: the first is Horizontal Distance Features (HDF) that is based on the distances between (Ankles, knees, hands, shoulders), the second set is the Vertical Distance Features (VDF) that provide significant information of human gait extracted from the height to the ground of (hand, shoulder, and ankles) during one gait cycle. Extracting these two sets of feature are difficult and not accurate based on using traditional camera, therefore the Kinect sensor is used in this paper to determine the precise measurements. The two sets of feature are separately tested and then fused to create one feature vector. A database has been created in house to perform our experiments. This database consists of sixteen males and four females. For each individual, 10 videos have been recorded, each record includes in average two gait cycles. The Kinect sensor is used here to extract all the skeleton points, and these points are used to build up the feature vectors mentioned above. K-nearest neighbor is used as the classification method based on Cityblock distance function. Based on the experimental result the proposed method provides 56% as a recognition rate using HDF, while VDF provided 83.5% recognition accuracy. When fusing both of the HDF and VDF as one feature vector, the recognition rate increased to 92%, the experimental result shows that our method provides significant result compared to the existence methods.

  12. Intersegmental coordination of gait after hemorrhagic stroke.

    PubMed

    Chow, John W; Stokic, Dobrivoje S

    2015-01-01

    We compared gait using the planar law of intersegmental coordination between 14 hemorrhagic stroke subjects walking at a self-selected normal speed (56 ± 21 cm/s) and 15 age-matched healthy controls walking at a very slow speed (56 ± 19 cm/s). Sagittal plane elevation angles of the thigh, shank, and foot segments were submitted to principal component analysis. Additional outcome measures included the range of elevation angle and timing of peak elevation angle of the thigh, shank, and foot segments. The range of elevation angles at the shank and foot was significantly smaller in the paretic leg than non-paretic and control legs. Also, the peak elevation angle at the thigh occurred significantly later in the gait cycle in the paretic than control leg. Gait of both stroke and control subjects followed the planar law with the first two principal components explaining approximately 99% of the variance. However, the three-dimensional trajectory of elevation angles (gait loop) in stroke subjects deviated from the typical teardrop shape bilaterally, which was more exaggerated in the paretic leg. Compared to the non-paretic and control legs, the paretic leg showed significantly increased absolute loading of the thigh elevation angle and decreased absolute loadings of the shank and foot elevation angles on the first principal component, whereas the opposite was observed for the second principal component. Despite following the planar law, the gait of chronic stroke subjects is characterized by atypical timing of the thigh motion and disrupted intersegmental coordination of both legs. PMID:25224705

  13. Effects of gait velocity and center of mass acceleration during turning gait in old-old elderly women

    PubMed Central

    Shin, Sun-Shil; Yoo, Won-Gyu

    2015-01-01

    [Purpose] This study investigated gait velocity and center of mass acceleration in three directions during square and semicircular turning gait tasks in old-old elderly women. [Subjects] Fifteen community-dwelling, old-old elderly women (≥75 years old) who could walk independently were recruited. [Methods] We measured gait velocity and center of mass acceleration in three directions using an accelerometer during two different turning gait tasks. [Results] The velocity during square turning was significantly slower than that during semicircular turning gait. There were no significant differences between gait tasks with respect to normalized antero-posterior, medo-lateral, or vertical center of mass acceleration. [Conclusion] Changing the direction of travel while walking regardless of turning angle is one of the greatest challenges for balance in old-old elderly people. Furthermore, gait velocity is a useful clinical marker for predicting falls in old-old elderly populations. PMID:26180319

  14. Effectiveness of elastic band-type ankle–foot orthoses on postural control in poststroke elderly patients as determined using combined measurement of the stability index and body weight-bearing ratio

    PubMed Central

    Kim, Jong Hyun; Sim, Woo Sang; Won, Byeong Hee

    2015-01-01

    Purpose Poor recovery of postural stability poststroke is the primary cause of impairment in activities and social participation in elderly stroke survivors. The purpose of our study was to experimentally evaluate the effectiveness of our new elastic ankle–foot orthosis (AFO), compared to a traditional AFO fabricated with hard plastic, in improving postural stability in elderly chronic stroke survivors. Patients and methods Postural stability was evaluated in ten chronic stroke patients, 55.7±8.43 years old. Postural stability was evaluated using the standardized methods of the Biodex Balance System combined with a foot pressure system, under three experimental conditions, no AFO, rigid plastic AFO, and elastic AFO (E-AFO). The following dependent variables of postural stability were analyzed: plantar pressure under the paretic and nonparetic foot, area of the center of balance (COB) and % time spent in each location, distance traveled by the COB away from the body center, distance traveled by the center of pressure, and calculated index of overall stability, as well as indices anterior–posterior and medial–lateral stability. Results Both AFO designs improved all indices of postural stability. Compared to the rigid plastic AFO, the E-AFO produced additional positive effects in controlling anterior–posterior body sway, equalizing weight bearing through the paretic and nonparetic limbs, and restraining the displacement of the center of pressure and of the COB. Conclusion Based on our outcomes, we recommend the prescription of E-AFOs as part of a physiotherapy rehabilitation program to promote recovery of postural stability poststroke. When possible, therapeutic outcomes should be documented using the Biodex Balance System and foot pressure system, as used in our study, to provide evidence needed to support the development of a larger controlled trial to generate high-quality evidence on the effectiveness of E-AFOs. PMID:26622174

  15. Effects of frontal and sagittal thorax attitudes in gait on trunk and pelvis three-dimensional kinematics.

    PubMed

    Begon, Mickaël; Leardini, Alberto; Belvedere, Claudio; Farahpour, Nader; Allard, Paul

    2015-10-01

    While sagittal trunk inclinations alter upper body biomechanics, little is known about the extent of frontal trunk bending on upper body and pelvis kinematics in adults during gait and its relation to sagittal trunk inclinations. The objective was to determine the effect of the mean lateral trunk attitude on upper body and pelvis three-dimensional kinematics during gait in asymptomatic subjects. Three gait cycles were collected in 30 subjects using a motion analysis system (Vicon 612) and an established protocol. Sub-groups were formed based on the mean thorax lateral bending angle, bending side, and also sagittal tilt. These were compared based on 38 peak angles identified on pelvis, thorax and shoulder kinematics using MANOVAs. A main effect for bending side (p = 0.038) was found, especially for thorax peak angles. Statistics revealed also a significant interaction (p = 0.04993) between bending side and tilt for the thorax sagittal inclination during body-weight transfer. These results reinforce the existence of different gait patterns, which correlate upper body and pelvis motion measures. The results also suggest that frontal and sagittal trunk attitude should be considered carefully when treating a patient with impaired gait. PMID:26337553

  16. Kinematic analysis quantifies gait abnormalities associated with lameness in broiler chickens and identifies evolutionary gait differences.

    PubMed

    Caplen, Gina; Hothersall, Becky; Murrell, Joanna C; Nicol, Christine J; Waterman-Pearson, Avril E; Weeks, Claire A; Colborne, G Robert

    2012-01-01

    This is the first time that gait characteristics of broiler (meat) chickens have been compared with their progenitor, jungle fowl, and the first kinematic study to report a link between broiler gait parameters and defined lameness scores. A commercial motion-capturing system recorded three-dimensional temporospatial information during walking. The hypothesis was that the gait characteristics of non-lame broilers (n?=?10) would be intermediate to those of lame broilers (n?=?12) and jungle fowl (n?=?10, tested at two ages: immature and adult). Data analysed using multi-level models, to define an extensive range of baseline gait parameters, revealed inter-group similarities and differences. Natural selection is likely to have made jungle fowl walking gait highly efficient. Modern broiler chickens possess an unbalanced body conformation due to intense genetic selection for additional breast muscle (pectoral hypertrophy) and whole body mass. Together with rapid growth, this promotes compensatory gait adaptations to minimise energy expenditure and triggers high lameness prevalence within commercial flocks; lameness creating further disruption to the gait cycle and being an important welfare issue. Clear differences were observed between the two lines (short stance phase, little double-support, low leg lift, and little back displacement in adult jungle fowl; much double-support, high leg lift, and substantial vertical back movement in sound broilers) presumably related to mass and body conformation. Similarities included stride length and duration. Additional modifications were also identified in lame broilers (short stride length and duration, substantial lateral back movement, reduced velocity) presumably linked to musculo-skeletal abnormalities. Reduced walking velocity suggests an attempt to minimise skeletal stress and/or discomfort, while a shorter stride length and time, together with longer stance and double-support phases, are associated with instability. We envisage a key future role for this highly quantitative methodology in pain assessment (associated with broiler lameness) including experimental examination of therapeutic agent efficacy. PMID:22815823

  17. Kinematic Analysis Quantifies Gait Abnormalities Associated with Lameness in Broiler Chickens and Identifies Evolutionary Gait Differences

    PubMed Central

    Caplen, Gina; Hothersall, Becky; Murrell, Joanna C.; Nicol, Christine J.; Waterman-Pearson, Avril E.; Weeks, Claire A.; Colborne, G. Robert

    2012-01-01

    This is the first time that gait characteristics of broiler (meat) chickens have been compared with their progenitor, jungle fowl, and the first kinematic study to report a link between broiler gait parameters and defined lameness scores. A commercial motion-capturing system recorded three-dimensional temporospatial information during walking. The hypothesis was that the gait characteristics of non-lame broilers (n = 10) would be intermediate to those of lame broilers (n = 12) and jungle fowl (n = 10, tested at two ages: immature and adult). Data analysed using multi-level models, to define an extensive range of baseline gait parameters, revealed inter-group similarities and differences. Natural selection is likely to have made jungle fowl walking gait highly efficient. Modern broiler chickens possess an unbalanced body conformation due to intense genetic selection for additional breast muscle (pectoral hypertrophy) and whole body mass. Together with rapid growth, this promotes compensatory gait adaptations to minimise energy expenditure and triggers high lameness prevalence within commercial flocks; lameness creating further disruption to the gait cycle and being an important welfare issue. Clear differences were observed between the two lines (short stance phase, little double-support, low leg lift, and little back displacement in adult jungle fowl; much double-support, high leg lift, and substantial vertical back movement in sound broilers) presumably related to mass and body conformation. Similarities included stride length and duration. Additional modifications were also identified in lame broilers (short stride length and duration, substantial lateral back movement, reduced velocity) presumably linked to musculo-skeletal abnormalities. Reduced walking velocity suggests an attempt to minimise skeletal stress and/or discomfort, while a shorter stride length and time, together with longer stance and double-support phases, are associated with instability. We envisage a key future role for this highly quantitative methodology in pain assessment (associated with broiler lameness) including experimental examination of therapeutic agent efficacy. PMID:22815823

  18. Fluid lubricated bearing construction

    DOEpatents

    Dunning, John R.; Boorse, Henry A.; Boeker, Gilbert F.

    1976-01-01

    1. A fluid lubricated thrust bearing assembly comprising, in combination, a first bearing member having a plain bearing surface, a second bearing member having a bearing surface confronting the bearing surface of said first bearing member and provided with at least one spiral groove extending inwardly from the periphery of said second bearing member, one of said bearing members having an axial fluid-tight well, a source of fluid lubricant adjacent to the periphery of said second bearing member, and means for relatively rotating said bearing members to cause said lubricant to be drawn through said groove and to flow between said bearing surfaces, whereby a sufficient pressure is built up between said bearing surfaces and in said well to tend to separate said bearing surfaces.

  19. Estimates of circulation and gait change based on a three-dimensional kinematic analysis of flight in cockatiels (Nymphicus hollandicus) and ringed turtle-doves (Streptopelia risoria).

    PubMed

    Hedrick, Tyson L; Tobalske, Bret W; Biewener, Andrew A

    2002-05-01

    Birds and bats are known to employ two different gaits in flapping flight, a vortex-ring gait in slow flight and a continuous-vortex gait in fast flight. We studied the use of these gaits over a wide range of speeds (1-17 ms(-1)) and transitions between gaits in cockatiels (Nymphicus hollandicus) and ringed turtle-doves (Streptopelia risoria) trained to fly in a recently built, variable-speed wind tunnel. Gait use was investigated via a combination of three-dimensional kinematics and quasi-steady aerodynamic modeling of bound circulation on the distal and proximal portions of the wing. Estimates of lift from our circulation model were sufficient to support body weight at all but the slowest speeds (1 and 3 ms(-1)). From comparisons of aerodynamic impulse derived from our circulation analysis with the impulse estimated from whole-body acceleration, it appeared that our quasi-steady aerodynamic analysis was most accurate at intermediate speeds (5-11 ms(-1)). Despite differences in wing shape and wing loading, both species shifted from a vortex-ring to a continuous-vortex gait at 7 ms(-1). We found that the shift from a vortex-ring to a continuous-vortex gait (i) was associated with a phase delay in the peak angle of attack of the proximal wing section from downstroke into upstroke and (ii) depended on sufficient forward velocity to provide airflow over the wing during the upstroke similar to that during the downstroke. Our kinematic estimates indicated significant variation in the magnitude of circulation over the course the wingbeat cycle when either species used a continuous-vortex gait. This variation was great enough to suggest that both species shifted to a ladder-wake gait as they approached the maximum flight speed (cockatiels 15 ms(-1), doves 17 ms(-1)) that they would sustain in the wind tunnel. This shift in flight gait appeared to reflect the need to minimize drag and produce forward thrust in order to fly at high speed. The ladder-wake gait was also employed in forward and vertical acceleration at medium and fast flight speeds. PMID:11976351

  20. Alpine Skiing With total knee ArthroPlasty (ASWAP): effects on gait asymmetries.

    PubMed

    Pötzelsberger, B; Lindinger, S J; Stöggl, T; Buchecker, M; Müller, E

    2015-08-01

    The aim of the study was to examine the effect of a 12-week recreational skiing intervention on functional gait performance in people with unilateral total knee arthroplasty (TKA). Twenty-three older adults (71 ± 5 years) were assigned to the intervention (IG) or control group (CG). Test time and ground reaction forces (GRF) were recorded at pre- and post-intervention and in the retention phase during functional gait tests. Ground contact was recorded bilaterally and divided into the weight acceptance and push-off phases. In IG, a faster stair descent time (16%) was observed at post-test with no further change at the retention test. The asymmetry indices for all analyzed variables were decreased in stair descent and during weight acceptance in stair ascent and level walking without further changes between post- and retention test. The reduced asymmetries occurred mainly because of increased loading of the operated leg. Most variables were unchanged in CG. Similar to the force data, the asymmetry index for temporal stride characteristics was reduced in all stair descent variables. These results demonstrate that alpine skiing as a leisure-time activity has a beneficial effect on gait performance and leads to a more balanced load distribution between the legs during daily activities. PMID:26083702

  1. Muscle strength training to improve gait function in children with cerebral palsy.

    PubMed

    Eek, Meta Nyström; Tranberg, Roy; Zügner, Roland; Alkema, Kristina; Beckung, Eva

    2008-10-01

    The aim of the study was to investigate the influence of muscle strength training on gait outcomes in children with cerebral palsy. Sixteen children (two females, 14 males, Gross Motor Function Classification System levels I-II, mean age 12y 6mo, range 9y 4mo-15y 4mo) underwent muscle strength measurement using a handheld device, Gross Motor Function Measure (GMFM) assessment, three-dimensional gait analysis, joint range of motion assessment, and grading of spasticity before and after 8 weeks of training. All participants had a diagnosis of spastic diplegia and could walk without aids. Training consisted of exercises for lower extremity muscles with free weights, rubber bands, and body weight for resistance, three times a week. Values for muscle strength below normal were identified in all children; this was most pronounced at the ankle, followed by the hip muscles. After training, muscle strength and GMFM scores increased, velocity was unchanged, stride length increased, and cadence was reduced. There was an increase in hip extensor moment and power generated at push off. Eight weeks of muscle strength training can increase muscle strength and improve gait function. PMID:18834389

  2. Changes in Gait Variability From First Steps to Adulthood: Normative Data for the Gait Variability Index.

    PubMed

    Gouelle, Arnaud; Leroux, Julien; Bredin, Jonathan; Mégrot, Fabrice

    2016-01-01

    The process of learning to walk is ongoing throughout childhood. The Gait Variability Index (GVI; A. Gouelle et al., 2013) has been proposed to quantify the variability of spatiotemporal parameters (STP) during gait. The authors' aim was to evaluate the GVI and STP of healthy children and teenagers to (a) determine changes in the GVI with age and to derive normal values in children and (b) to evaluate the influence of STP on the GVI. A total of 140 typically developing children from 1 to 17 years old were categorized into 7 groups of 20 based on age. Spatiotemporal gait parameters were recorded using an electronic walkway. GVI increased and STP changed with age. In the children-teenagers group, the GVI was positively related to step length, speed, and negatively to cadence. Following normalization by lower limb length, correlations were no longer significant. In contrast, raw base of support was not correlated with the GVI but normalized base of support was. A multiple linear regression showed that only age had a direct impact on the GVI, indicating that gait continues to change after 6-7 years. These changes were only demonstrated by the GVI, highlighting its usefulness for the evaluation of gait in young populations. PMID:26392028

  3. The effects of gait velocity on the gait characteristics of hemiplegic patients

    PubMed Central

    You, Young Youl; Chung, Sin Ho

    2015-01-01

    [Purpose] The present study investigated the effects of gait speed on temporal and spatial gait characteristics of hemiplegic stroke patients. [Subjects and Methods] Twenty post-stroke hemiplegic patients participated in the present study. To enhance the reliability of the analysis of the gait characteristics, the assessments were conducted three days per week at the same time every day. Each subject walked maintaining a comfortable speed for the first minute, and measurement was conducted for 30 seconds at a treadmill speed of 1 km/hour thereafter. Then, the subjects walked at a treadmill speed of 2 km/hour for 30 seconds after a 30-minute rest. The differences in the measurements were tested for significance using the paired t-test. [Results] The measures of foot rotation, step width, load response, mid stance, pre-swing, swing phase, and double stance phase showed significant difference between the gait velocities. [Conclusion] The present study provides basic data for gait velocity changes for hemiplegic patients. PMID:25931759

  4. The golden ratio of gait harmony: repetitive proportions of repetitive gait phases.

    PubMed

    Iosa, Marco; Fusco, Augusto; Marchetti, Fabio; Morone, Giovanni; Caltagirone, Carlo; Paolucci, Stefano; Peppe, Antonella

    2013-01-01

    In nature, many physical and biological systems have structures showing harmonic properties. Some of them were found related to the irrational number φ known as the golden ratio that has important symmetric and harmonic properties. In this study, the spatiotemporal gait parameters of 25 healthy subjects were analyzed using a stereophotogrammetric system with 25 retroreflective markers located on their skin. The proportions of gait phases were compared with φ, the value of which is about 1.6180. The ratio between the entire gait cycle and stance phase resulted in 1.620 ± 0.058, that between stance and the swing phase was 1.629 ± 0.173, and that between swing and the double support phase was 1.684 ± 0.357. All these ratios did not differ significantly from each other (F = 0.870, P = 0.422, repeated measure analysis of variance) or from φ (P = 0.670, 0.820, 0.422, resp., t-tests). The repetitive gait phases of physiological walking were found in turn in repetitive proportions with each other, revealing an intrinsic harmonic structure. Harmony could be the key for facilitating the control of repetitive walking. Harmony is a powerful unifying factor between seemingly disparate fields of nature, including human gait. PMID:23862161

  5. Cryogenic turbopump bearing materials

    NASA Technical Reports Server (NTRS)

    Bhat, Biliyar N.

    1989-01-01

    Materials used for modern cryogenic turbopump bearings must withstand extreme conditions of loads and speeds under marginal lubrication. Naturally, these extreme conditions tend to limit the bearing life. It is possible to significantly improve the life of these bearings, however, by improving the fatigue and wear resistance of bearing alloys, and improving the strength, liquid oxygen compatibility and lubricating ability of the bearing cage materials. Improved cooling will also help to keep the bearing temperatures low and hence prolong the bearing life.

  6. RELATIONSHIP OF GAIT AND COGNITION IN THE ELDERLY

    PubMed Central

    Parihar, Raminder; Mahoney, Jeannette R.; Verghese, Joe

    2013-01-01

    Gait and cognitive impairments in older adults mostly reflect the co-occurrence of two geriatric syndromes linked by common underlying brain substrates and pathologies. Gait control is predominately mediated by frontal subcortical circuits, which overlap with circuits controlling executive control and attention functions. These circuits are vulnerable to multiple age-related pathologies such as ischemia, inflammation, and neurodegeneration, which could ultimately cause cognitive, gait, or combined cognitive and gait impairments. The following review aims to describe various gait and cognitive classifications, gait based phenotypes, common underlying pathological processes, and provide a link between motor and cognitive impairments in an effort to predict the risk of dementia, as well as remediate impairments by applying appropriate interventions. PMID:24349877

  7. Experimentally Derived Kinetic Model for Sensor-Based Gait Monitoring.

    PubMed

    Ketema, Yohannes; Gebre-Egziabher, Demoz

    2016-01-01

    A method for estimating gait parameters (shank, thigh, and stance leg angles) from a single, in situ, scalar acceleration measurement is presented. A method for minimizing the impact of errors due to unpredictable variations in muscle actuation and acceleration measurement biases is developed. This is done by determining the most probable gait progression by minimization of a cost function that reflects the size of errors in the gait parameters. In addition, a model for gait patterns that takes into account their variations due to walking speed is introduced and used. The approach is tested on data collected from subjects in a gait study. The approach can estimate limb angles with errors less than 6 deg (one standard deviation) and, thus, is suitable for many envisioned gait monitoring applications in nonlaboratory settings. PMID:26593150

  8. Effects of orthosis on balance and gait in healthy adults

    PubMed Central

    Kim, Myung-Joon; Choi, Yeong-Deok; Lee, Jung-Ho

    2015-01-01

    [Purpose] This study evaluated the effects of an oral orthosis that can change body alignment on the balance ability and gait of healthy adults. [Subjects and Methods] The subjects of this study were 21 University students. A gait analyzer was used to analyze the subjects’ balance ability and gait quality. Two walking speeds were used: 2 km/h, a comfortable speed, and 4 km/h, a slightly faster walking speed. [Results] The step length, and base of gait at 2 km/h differed significantly after the intervention. The total step time and step length increased significantly after the intervention. Furthermore, the total base of gait decreased significantly after the intervention. The step times of the left lower limb at 4 km/h differed significantly after the intervention. [Conclusion] The oral orthosis tested positively affects the balance ability and gait of healthy adults. PMID:26180365

  9. Autonomous Evolution of Dynamic Gaits with Two Quadruped Robots

    NASA Technical Reports Server (NTRS)

    Hornby, Gregory S.; Takamura, Seichi; Yamamoto, Takashi; Fujita, Masahiro

    2004-01-01

    A challenging task that must be accomplished for every legged robot is creating the walking and running behaviors needed for it to move. In this paper we describe our system for autonomously evolving dynamic gaits on two of Sony's quadruped robots. Our evolutionary algorithm runs on board the robot and uses the robot's sensors to compute the quality of a gait without assistance from the experimenter. First we show the evolution of a pace and trot gait on the OPEN-R prototype robot. With the fastest gait, the robot moves at over 10/min/min., which is more than forty body-lengths/min. While these first gaits are somewhat sensitive to the robot and environment in which they are evolved, we then show the evolution of robust dynamic gaits, one of which is used on the ERS-110, the first consumer version of AIBO.

  10. Treatment of Gait Ignition Failure with Ropinirole

    PubMed Central

    Cohen-Oram, Alexis N.; Stewart, Jonathan T.; Bero, Kim; Hoffmann, Michael W.

    2014-01-01

    Gait ignition failure (GIF) is a syndrome characterized by hesitation or inability to initiate gait from a static position. It may occur in a variety of conditions, including normal pressure hydrocephalus, subcortical vascular disease, parkinsonian syndromes and a variety of focal lesions. Previous information on the treatment of GIF has been primarily anecdotal, but there have been a few reports of response to dopamine agonists. We report a 63-year-old man with anoxic encephalopathy who developed GIF nine years after the initial anoxic insult. The patient’s GIF responded robustly, albeit transiently, to ropinirole. MRI was unrevealing, but a positron emission tomography scan showed hypometabolism in the deep frontal ACA/MCA watershed area; this may have disconnected the basal ganglia from the motor cortex and/or interrupted dopaminergic mesocortical transmission. Our understanding of the pathophysiology and the treatment of GIF remains limited, but there may be at least a limited therapeutic role for dopamine agonists. PMID:25360234

  11. [Freezing and gait disorders in Parkinson's disease].

    PubMed

    Gonçalves, Giovanna; Pereira, João

    2013-06-01

    More than one third of patients with Parkinson disease experience freezing. It is characterized by the feeling that one's feet are "glued to the floor", and it is more common in the later stages of the disease. The causes of this gait disorder are not yet fully established, but it may lead patients to suffer falls and lose their independence. As a consequence, the development of therapeutic measures which can overcome freezing is of fundamental important for the autonomy of such individuals. There is no consensus in the literature on the most recommended therapeutic measures for the prevention or attenuation of freezing in gait. What seems to be defined are the phenomenological aspects of the disorder and good therapy, represented by the association between drug therapy and sensorial stimuli or motor coordination training geared towards the specificities to avoid motor difficulties of freezing, when triggering factors are present. PMID:24121579

  12. Kinematic gait analysis in equine carpal lameness.

    PubMed

    Back, W; Barneveld, A; van Weeren, P R; van den Bogert, A J

    1993-01-01

    Gait analysis plays a major role in the clinical evaluation of equine lameness. It is generally accepted that the clinician expresses the grade of lameness as a subjective score. In this study lameness was objectively assessed using a standardized transient lameness model, in which lameness was induced by intra-articular injection of bacterial endotoxin into the radiocarpal joint of ponies. Lameness was scored by an experienced clinician, and locomotion was recorded simultaneously using a CODA-3 apparatus. The obtained kinematic gait parameters correlated well with the clinical lameness score and also provided possibilities to objectively study the locomotor disturbances of the lame limb in more detail at the walk and trot. PMID:8470470

  13. Locomotion gaits of a rotating cylinder pair

    NASA Astrophysics Data System (ADS)

    van Rees, Wim M.; Novati, Guido; Koumoutsakos, Petros; Mahadevan, L.

    2015-11-01

    Using 2D numerical simulations of the Navier-Stokes equations, we demonstrate that a simple pair of rotating cylinders can display a range of locomotion patterns of biological and engineering interest. Steadily counter-rotating the cylinders causes the pair to move akin to a vortex dipole for low rotation rates, but as the rotational velocity is increased the direction of motion reverses. Unsteady rotations lead to different locomotion gaits that resemble jellyfish (for in-phase rotations) and undulating swimmers (for out-of-phase rotations). The small number of parameters for this simple system allows us to systematically map the phase space of these gaits, and allows us to understand the underlying physical mechanisms using a minimal model with implications for biological locomotion and engineered analogs.

  14. Gait attentional load at different walking speeds.

    PubMed

    Nascimbeni, Alberto; Minchillo, Marco; Salatino, Adriana; Morabito, Ursula; Ricci, Raffaella

    2015-01-01

    Gait is an attention-demanding task even in healthy young adults. However, scant evidence exists about the attentional load required at various walking speeds. The aim of this study was to investigate motor-cognitive interference while walking at spontaneous, slow and very slow speed on a treadmill while carrying out a backward counting task, in a group (n = 22) of healthy young participants. Cognitive performance was also assessed while sitting. Higher DT cost on the cognitive task was found at spontaneous and very slow walking speed, while at slow walking speed the cognitive task was prioritized with higher DT cost on the motor task. The attentional allocation during DT depends on walking speed with gait prioritization at spontaneous and very slow speed that likely represent more challenging motor conditions. PMID:25270327

  15. Extraction and Classification of Human Gait Features

    NASA Astrophysics Data System (ADS)

    Ng, Hu; Tan, Wooi-Haw; Tong, Hau-Lee; Abdullah, Junaidi; Komiya, Ryoichi

    In this paper, a new approach is proposed for extracting human gait features from a walking human based on the silhouette images. The approach consists of six stages: clearing the background noise of image by morphological opening; measuring of the width and height of the human silhouette; dividing the enhanced human silhouette into six body segments based on anatomical knowledge; applying morphological skeleton to obtain the body skeleton; applying Hough transform to obtain the joint angles from the body segment skeletons; and measuring the distance between the bottom of right leg and left leg from the body segment skeletons. The angles of joints, step-size together with the height and width of the human silhouette are collected and used for gait analysis. The experimental results have demonstrated that the proposed system is feasible and achieved satisfactory results.

  16. Neglected Alkaptonuric Patient Presenting with Steppage Gait

    PubMed Central

    Mirzashahi, Babak; Tafakhori, Abbas; Najafi, Arvin; Farzan, Mahmoud

    2016-01-01

    Even though intervertebral disc degeneration can be found in the natural course of alkaptonuria, detection of the disease by black disc color change in a patient without any other presentation of alkaptonuria is an exceptionally rare condition. We have reported a very rare case of alkaptonuria presented with low back pain and steppage gait in a 51-year-old male with a complaint of chronic low-back pain and steppage gait who was operated on for prolapsed lumbar disc herniation. Intraoperatively his lumbar disk was discovered to be black. The alkaptonuria diagnosis was considered after histopathological examination of the black disc material and elevated urinary concentration of homogentisic acid confirmed the diagnosis. To our knowledge, this presentation has not been reported previously in literature. PMID:27200402

  17. An efficient robotic tendon for gait assistance.

    PubMed

    Hollander, Kevin W; Ilg, Robert; Sugar, Thomas G; Herring, Donald

    2006-10-01

    A robotic tendon is a spring based, linear actuator in which the stiffness of the spring is crucial for its successful use in a lightweight, energy efficient, powered ankle orthosis. Like its human analog, the robotic tendon uses its inherent elastic nature to reduce both peak power and energy requirements for its motor. In the ideal example, peak power required of the motor for ankle gait is reduced from 250 W to just 77 W. In addition, ideal energy requirements are reduced from nearly 36 J to just 21 J. Using this approach, an initial prototype has provided 100% of the power and energy necessary for ankle gait in a compact 0.95 kg package, seven times less than an equivalent motor/gearbox system. PMID:16995768

  18. Office management of gait disorders in the elderly

    PubMed Central

    Lam, Robert

    2011-01-01

    Abstract Objective To provide family physicians with an approach to office management of gait disorders in the elderly. Sources of information Ovid MEDLINE was searched from 1950 to July 2010 using subject headings for gait or neurologic gait disorders combined with physical examination. Articles specific to family practice or family physicians were selected. Relevant review articles and original research were used when appropriate and applicable to the elderly. Main message Gait and balance disorders in the elderly are difficult to recognize and diagnose in the family practice setting because they initially present with subtle undifferentiated manifestations, and because causes are usually multifactorial, with multiple diseases developing simultaneously. To further complicate the issue, these manifestations can be camouflaged in elderly patients by the physiologic changes associated with normal aging. A classification of gait disorders based on sensorimotor levels can be useful in the approach to management of this problem. Gait disorders in patients presenting to family physicians in the primary care setting are often related to joint and skeletal problems (lowest-level disturbances), as opposed to patients referred to neurology specialty clinics with sensory ataxia, myelopathy, multiple strokes, and parkinsonism (lowest-, middle-, and highest-level disturbances). The difficulty in diagnosing gait disorders stems from the challenge of addressing early undifferentiated disease caused by multiple disease processes involving all sensorimotor levels. Patients might present with a nonspecific “cautious” gait that is simply an adaptation of the body to disease limitations. This cautious gait has a mildly flexed posture with reduced arm swing and a broadening of the base of support. This article reviews the focused history (including medication review), practical physical examination, investigations, and treatments that are key to office management of gait disorders. Conclusion Family physicians will find it helpful to classify gait disorders based on sensorimotor level as part of their approach to office management of elderly patients. Managing gait disorders at early stages can help prevent further deconditioning and mobility impairment. PMID:21753097

  19. Brain activation pattern related to gait disturbances in Parkinson's disease.

    PubMed

    Crémers, Julien; D'Ostilio, Kevin; Stamatakis, Julien; Delvaux, Valérie; Garraux, Gaëtan

    2012-10-01

    Gait disturbances represent a therapeutic challenge in Parkinson's disease (PD). To further investigate their underlying pathophysiological mechanisms, we compared brain activation related to mental imagery of gait between 15 PD patients and 15 age-matched controls using a block-design functional MRI experiment. On average, patients showed altered locomotion relatively to controls, as assessed with a standardized gait test that evaluated the severity of PD-related gait disturbances on a 25-m path. The experiment was conducted in the subjects as they rehearsed themselves walking on the same path with a gait pattern similar as that during locomotor evaluation. Imagined walking times were measured on a trial-by-trial basis as a control of behavioral performance. In both groups, mean imagined walking time was not significantly different from that measured during real gait on the path used for evaluation. The between-group comparison of the mental gait activation pattern with reference to mental imagery of standing showed hypoactivations within parieto-occipital regions, along with the left hippocampus, midline/lateral cerebellum, and presumed pedunculopontine nucleus/mesencephalic locomotor area, in patients. More specifically, the activation level of the right posterior parietal cortex located within the impaired gait-related cognitive network decreased proportionally with the severity of gait disturbances scored on the path used for gait evaluation and mental imagery. These novel findings suggest that the right posterior parietal cortex dysfunction is strongly related to the severity of gait disturbances in PD. This region may represent a target for the development of therapeutic interventions for PD-related gait disturbances. PMID:23008169

  20. Delayed gait recovery in a stroke patient☆

    PubMed Central

    Seo, Jeong Pyo; Lee, Mi Young; Kwon, Yong Hyun; Jang, Sung Ho

    2013-01-01

    We report on a stroke patient who showed delayed gait recovery between 8 and 11 months after the onset of intracerebral hemorrhage. This 32-year-old female patient underwent craniotomy and drainage for right intracerebral hemorrhage due to rupture of an arteriovenous malformation. Brain MR images revealed a large leukomalactic lesion in the right fronto-parietal cortex. Diffusion tensor tractography at 8 months after onset revealed that the right corticospinal tract was severely injured. At this time, the patient could not stand or walk despite undergoing rehabilitation from 2 months after onset. It was believed that severe spasticity of the left leg and right ankle was largely responsible, and thus, antispastic drugs, antispastic procedures (alcohol neurolysis of the motor branch of the tibial nerve and an intramuscular alcohol wash of both tibialis posterior muscles) and physical therapy were tried to control the spasticity. These measures relieved the severe spasticity, with the result that the patient was able to stand at 3 months. In addition, the improvements in sensorimotor function, visuospatial function, and cognition also seemed to contribute to gait recovery. As a result, she gained the ability to walk independently on even floor with a left ankle foot orthosis at 11 months after onset. This case illustrates that clinicians should attempt to find the cause of gait inability and to initiate intensive rehabilitation in stroke patients who cannot walk at 3–6 months after onset. PMID:25206447

  1. Fractional Langevin model of gait variability

    PubMed Central

    West, Bruce J; Latka, Miroslaw

    2005-01-01

    The stride interval in healthy human gait fluctuates from step to step in a random manner and scaling of the interstride interval time series motivated previous investigators to conclude that this time series is fractal. Early studies suggested that gait is a monofractal process, but more recent work indicates the time series is weakly multifractal. Herein we present additional evidence for the weakly multifractal nature of gait. We use the stride interval time series obtained from ten healthy adults walking at a normal relaxed pace for approximately fifteen minutes each as our data set. A fractional Langevin equation is constructed to model the underlying motor control system in which the order of the fractional derivative is itself a stochastic quantity. Using this model we find the fractal dimension for each of the ten data sets to be in agreement with earlier analyses. However, with the present model we are able to draw additional conclusions regarding the nature of the control system guiding walking. The analysis presented herein suggests that the observed scaling in interstride interval data may not be due to long-term memory alone, but may, in fact, be due partly to the statistics. PMID:16076394

  2. Gait correlation analysis based human identification.

    PubMed

    Chen, Jinyan

    2014-01-01

    Human gait identification aims to identify people by a sequence of walking images. Comparing with fingerprint or iris based identification, the most important advantage of gait identification is that it can be done at a distance. In this paper, silhouette correlation analysis based human identification approach is proposed. By background subtracting algorithm, the moving silhouette figure can be extracted from the walking images sequence. Every pixel in the silhouette has three dimensions: horizontal axis (x), vertical axis (y), and temporal axis (t). By moving every pixel in the silhouette image along these three dimensions, we can get a new silhouette. The correlation result between the original silhouette and the new one can be used as the raw feature of human gait. Discrete Fourier transform is used to extract features from this correlation result. Then, these features are normalized to minimize the affection of noise. Primary component analysis method is used to reduce the features' dimensions. Experiment based on CASIA database shows that this method has an encouraging recognition performance. PMID:24592144

  3. Gait Signal Analysis with Similarity Measure

    PubMed Central

    Shin, Seungsoo

    2014-01-01

    Human gait decision was carried out with the help of similarity measure design. Gait signal was selected through hardware implementation including all in one sensor, control unit, and notebook with connector. Each gait signal was considered as high dimensional data. Therefore, high dimensional data analysis was considered via heuristic technique such as the similarity measure. Each human pattern such as walking, sitting, standing, and stepping up was obtained through experiment. By the results of the analysis, we also identified the overlapped and nonoverlapped data relation, and similarity measure analysis was also illustrated, and comparison with conventional similarity measure was also carried out. Hence, nonoverlapped data similarity analysis provided the clue to solve the similarity of high dimensional data. Considered high dimensional data analysis was designed with consideration of neighborhood information. Proposed similarity measure was applied to identify the behavior patterns of different persons, and different behaviours of the same person. Obtained analysis can be extended to organize health monitoring system for specially elderly persons. PMID:25110724

  4. Gait patterns for crime fighting: statistical evaluation

    NASA Astrophysics Data System (ADS)

    Sulovská, Kateřina; Bělašková, Silvie; Adámek, Milan

    2013-10-01

    The criminality is omnipresent during the human history. Modern technology brings novel opportunities for identification of a perpetrator. One of these opportunities is an analysis of video recordings, which may be taken during the crime itself or before/after the crime. The video analysis can be classed as identification analyses, respectively identification of a person via externals. The bipedal locomotion focuses on human movement on the basis of their anatomical-physiological features. Nowadays, the human gait is tested by many laboratories to learn whether the identification via bipedal locomotion is possible or not. The aim of our study is to use 2D components out of 3D data from the VICON Mocap system for deep statistical analyses. This paper introduces recent results of a fundamental study focused on various gait patterns during different conditions. The study contains data from 12 participants. Curves obtained from these measurements were sorted, averaged and statistically tested to estimate the stability and distinctiveness of this biometrics. Results show satisfactory distinctness of some chosen points, while some do not embody significant difference. However, results presented in this paper are of initial phase of further deeper and more exacting analyses of gait patterns under different conditions.

  5. Gait analysis of a radial symmetrical hexapod robot based on parallel mechanisms

    NASA Astrophysics Data System (ADS)

    Xu, Kun; Ding, Xilun

    2014-09-01

    Most gait studies of multi-legged robots in past neglected the dexterity of robot body and the relationship between stride length and body height. This paper investigates the performance of a radial symmetrical hexapod robot based on the dexterity of parallel mechanism. Assuming the constraints between the supporting feet and the ground with hinges, the supporting legs and the hexapod body are taken as a parallel mechanism, and each swing leg is regarded as a serial manipulator. The hexapod robot can be considered as a series of hybrid serial-parallel mechanisms while walking on the ground. Locomotion performance can be got by analyzing these equivalent mechanisms. The kinematics of the whole robotic system is established, and the influence of foothold position on the workspace of robot body is analyzed. A new method to calculate the stride length of multi-legged robots is proposed by analyzing the relationship between the workspaces of two adjacent equivalent parallel mechanisms in one gait cycle. Referring to service region and service sphere, weight service sphere and weight service region are put forward to evaluate the dexterity of robot body. The dexterity of single point in workspace and the dexterity distribution in vertical and horizontal projection plane are demonstrated. Simulation shows when the foothold offset goes up to 174 mm, the dexterity of robot body achieves its maximum value 0.1644 in mixed gait. The proposed methods based on parallel mechanisms can be used to calculate the stride length and the dexterity of multi-legged robot, and provide new approach to determine the stride length, body height, footholds in gait planning of multi-legged robot.

  6. Redundant Bearing Assembly

    NASA Technical Reports Server (NTRS)

    Wright, Jay M.

    1995-01-01

    Proposed redundant bearing assembly consists of two modified ball or roller bearings, one held by other. Outer race of inner bearing press-fit into inner race of outer bearing. Within each bearing, side walls of inner and outer races extended radially toward each other leaving only small gap. In assembly, one bearing continues to allow free rotation when other fails. Bearing wear monitored by examination of gaps between races. In alternative design, inner race of outer bearing and outer race of inner bearing manufactured as single piece.

  7. Temporal-spatial feature of gait after traumatic brain injury.

    PubMed

    Ochi, F; Esquenazi, A; Hirai, B; Talaty, M

    1999-04-01

    The temporal-spatial characteristics of the gait of patients with traumatic brain injury (TBI) were investigated and compared with those of normal gait and the gait of stroke survivors. A slower walking velocity is evident in the TBI population when compared with normal. The average walking speed of TBI survivors is faster than that of stroke patients and is mainly related to a longer step length. TBI survivors produce a gait pattern with a prolonged stance period for the unaffected limb, without prolonged stance period for the affected limb, and a shorter step length for the unaffected limb. PMID:10191370

  8. Approach to the elderly patient with gait disturbance

    PubMed Central

    2012-01-01

    Summary The prevalence of gait disturbances and falls increases dramatically with age, but these problems are not universal in the elderly. They should trigger a systematic search for underlying disease states, many of which can be treated medically or surgically, or significantly ameliorated through provision of physical therapy focused on gait training and aids to ambulation, removal of safety hazards in the environment, and the elimination of polypharmacy. While cardiovascular, orthopedic, and rheumatologic diseases account for the majority of gait disturbances in the elderly, the aim here is to outline an approach to the diagnosis and treatment of a broad array of neurologic conditions causing gait disturbance in the elderly. PMID:23634361

  9. Age-Related Deviation of Gait from Normality in Alkaptonuria.

    PubMed

    Barton, Gabor J; King, Stephanie L; Robinson, Mark A; Hawken, Malcolm B; Ranganath, Lakshminarayan R

    2015-01-01

    Alkaptonuria is a rare metabolic disease leading to systemic changes including early and severe arthropathy which affects mobility. For unknown reasons, the onset of degenerative changes is delayed to around 30 years of age when both objective and subjective symptoms develop. In order to complement description of the structural changes in alkaptonuria with measures of movement function, clinical gait analysis was added to the list of assessments in 2013. The aim of this study was to describe the deviation of gait from normality as a function of age in patients with alkaptonuria. Three-dimensional movement of reflective markers attached to joints were captured during walking in 39 patients and 10 controls. Subsequent to processing the data to emphasise the shape of marker trajectories, the mean Movement Deviation Profile was generated for all participants. This single number measure gives the deviation of a patient's gait from a distributed definition of gait normality. Results showed that gait deviation roughly follows a sigmoid profile with minimal increase of gait deviations in a younger patient group and an abrupt large increase around the second half of the 4th decade of life. Larger variations of gait deviations were found in the older group than in the younger group suggesting a complex interaction of multiple factors which determine gait function after symptoms manifest. Continued gait analysis of adults with AKU, extended to younger adults and children with AKU, is expected to complete understanding of both the natural history of alkaptonuria and how interventions can affect movement function. PMID:25786642

  10. Dynamic Principles of Gait and Their Clinical Implications

    PubMed Central

    Donelan, J. Maxwell

    2010-01-01

    A healthy gait pattern depends on an array of biomechanical features, orchestrated by the central nervous system for economy and stability. Injuries and other pathologies can alter these features and result in substantial gait deficits, often with detrimental consequences for energy expenditure and balance. An understanding of the role of biomechanics in the generation of healthy gait, therefore, can provide insight into these deficits. This article examines the basic principles of gait from the standpoint of dynamic walking, an approach that combines an inverted pendulum model of the stance leg with a pendulum model of the swing leg and its impact with the ground. The heel-strike at the end of each step has dynamic effects that can contribute to a periodic gait and its passive stability. Biomechanics, therefore, can account for much of the gait pattern, with additional motor inputs that are important for improving economy and stability. The dynamic walking approach can predict the consequences of disruptions to normal biomechanics, and the associated observations can help explain some aspects of impaired gait. This article reviews the basic principles of dynamic walking and the associated experimental evidence for healthy gait and then considers how the principles may be applied to clinical gait pathologies. PMID:20023002

  11. Effect of external cueing on gait in Huntington's disease.

    PubMed

    Delval, Arnaud; Krystkowiak, Pierre; Delliaux, Marie; Blatt, Jean-Louis; Derambure, Philippe; Destée, Alain; Defebvre, Luc

    2008-07-30

    In Huntington's disease (HD) patients, gait is characterized by a timing disorder with marked intraindividual variability in temporal gait parameters (caused by the presence of both hyperkinetic and hypokinetic features). We sought to determine the influence of use of a metronome on gait parameters in patients simultaneously performing motor or cognitive tasks that required attentional resources. The objective is to evaluate the influence of rhythmic cues on gait interference during self-regulated walking and a dual task paradigm in HD. Fifteen HD patients and 15 paired controls were asked to walk and simultaneously perform another motor task (carrying a tray with four full glasses) or a cognitive task (counting backwards). We evaluated the effect of a metronome (set at 100% and 120% of the subject's self-determined cadence) in three different task conditions (gait alone, gait + motor task, gait + cognitive task). The use of auditory cues during free gait and dual tasks did not improve kinematic parameters in HD patients, in contrast to the situation for control subjects (improvement in gait speed and cadence but not stride length when the metronome was set at 120% in all conditions). HD patients have difficulty in synchronizing their footsteps with a metronome, mainly due to attentional deficits. PMID:18512747

  12. SSM-HPC: Front View Gait Recognition Using Spherical Space Model with Human Point Clouds

    NASA Astrophysics Data System (ADS)

    Ryu, Jegoon; Kamata, Sei-Ichiro; Ahrary, Alireza

    In this paper, we propose a novel gait recognition framework - Spherical Space Model with Human Point Clouds (SSM-HPC) to recognize front view of human gait. A new gait representation - Marching in Place (MIP) gait is also introduced which preserves the spatiotemporal characteristics of individual gait manner. In comparison with the previous studies on gait recognition which usually use human silhouette images from image sequences, this research applies three dimensional (3D) point clouds data of human body obtained from stereo camera. The proposed framework exhibits gait recognition rates superior to those of other gait recognition methods.

  13. A portable system with sample rate of 250 Hz for characterization of knee and hip angles in the sagittal plane during gait

    PubMed Central

    2014-01-01

    Background Gait analysis and research have been developed to obtain characteristics of movement patterns of people while walking. However, traditional measuring systems present different drawbacks that reduce their use and application. Among those drawbacks one can find: high price, low sampling frequency and limiting number of steps to be analyzed. Traditional measuring gait systems carry out their measurement at frequencies oscillating between 60 to 100 Hz. It can be argued about the need of higher sampling rates for gait measurements. However small displacements of the knee or hip for example, cannot be seen with low frequencies required a more detailed sampling and higher frequency sampling. Bearing this in mind, in this paper is presented a 250 Hz system based on accelerometers for gait measurement, and the particularities of knee and hip angles during gait are highlighted. Methods The system was designed with a PCI data acquisition card instrumented with an FPGA to achieve a rate sample of 250 Hz. The accelerometers were placed in thighs and legs to calculate the joint angles of hip and knee in the sagittal plane. The angles were estimated using the acceleration polygon method without integrating the acceleration and without filters. Results The gait of thirty healthy people of Mexican phenotype was analyzed over a flat floor free of obstacles. The results showed the gait phases and particularities associated with the walking style and people's laterality; the movement patterns were similar in the thirty persons. Based on the results, the particularities as the maximum amplitude in the angles and the shape in the movement patterns were related to the anthropometry and people phenotype. Conclusions The sampling frequency was essential to record 340 samples in single gait cycle and so registering the gait cycle with its particularities. In this work were recorded an average of 8 to 10 gait cycles, and the results showed variation regarding works carried out in biomechanics laboratories; this variation was related to the method and reference frame used to obtain the joint angles and the accuracy of measurement system. PMID:24684720

  14. A mobile gait monitoring system for abnormal gait diagnosis and rehabilitation: a pilot study for Parkinson disease patients.

    PubMed

    Bae, Joonbum; Kong, Kyoungchul; Byl, Nancy; Tomizuka, Masayoshi

    2011-04-01

    Conventional gait rehabilitation treatment does not provide quantitative information on abnormal gait kinematics, and the match of the intervention strategy to the underlying clinical presentation may be limited by clinical expertise and experience. Also the effect of rehabilitation treatment may be reduced as the rehabilitation treatment is achieved only in a clinical setting. In this paper, a mobile gait monitoring system (MGMS) is proposed for the diagnosis of abnormal gait and rehabilitation. The proposed MGMS consists of Smart Shoes and a microsignal processor with a touch screen display. It monitors patients' gait by observing the ground reaction force (GRF) and the center of GRF, and analyzes the gait abnormality. Since visual feedback about patients' GRFs and normal GRF patterns are provided by the MGMS, patients can practice the rehabilitation treatment by trying to follow the normal GRF patterns without restriction of time and place. The gait abnormality proposed in this paper is defined by the deviation between the patient's GRFs and normal GRF patterns, which are constructed as GRF bands. The effectiveness of the proposed gait analysis methods with the MGMS has been verified by preliminary trials with patients suffering from gait disorders. PMID:21428679

  15. Bearing Remover And Presser

    NASA Technical Reports Server (NTRS)

    Boyce, Rex A.

    1995-01-01

    Document describes simple bearing-servicing tool consisting of only three parts capable of removing and replacing rotary bearing within race. Threaded drive operates between guide and pressure plate for dislodging bearing from race.

  16. Patient-cooperative control increases active participation of individuals with SCI during robot-aided gait training

    PubMed Central

    2010-01-01

    Background Manual body weight supported treadmill training and robot-aided treadmill training are frequently used techniques for the gait rehabilitation of individuals after stroke and spinal cord injury. Current evidence suggests that robot-aided gait training may be improved by making robotic behavior more patient-cooperative. In this study, we have investigated the immediate effects of patient-cooperative versus non-cooperative robot-aided gait training on individuals with incomplete spinal cord injury (iSCI). Methods Eleven patients with iSCI participated in a single training session with the gait rehabilitation robot Lokomat. The patients were exposed to four different training modes in random order: During both non-cooperative position control and compliant impedance control, fixed timing of movements was provided. During two variants of the patient-cooperative path control approach, free timing of movements was enabled and the robot provided only spatial guidance. The two variants of the path control approach differed in the amount of additional support, which was either individually adjusted or exaggerated. Joint angles and torques of the robot as well as muscle activity and heart rate of the patients were recorded. Kinematic variability, interaction torques, heart rate and muscle activity were compared between the different conditions. Results Patients showed more spatial and temporal kinematic variability, reduced interaction torques, a higher increase of heart rate and more muscle activity in the patient-cooperative path control mode with individually adjusted support than in the non-cooperative position control mode. In the compliant impedance control mode, spatial kinematic variability was increased and interaction torques were reduced, but temporal kinematic variability, heart rate and muscle activity were not significantly higher than in the position control mode. Conclusions Patient-cooperative robot-aided gait training with free timing of movements made individuals with iSCI participate more actively and with larger kinematic variability than non-cooperative, position-controlled robot-aided gait training. PMID:20828422

  17. Gait pattern of heifers before and after claw trimming: a high-speed cinematographic study on a treadmill.

    PubMed

    Meyer, S W; Weishaupt, M A; Nuss, K A

    2007-02-01

    The manner in which the claws contacted the ground at the walk was evaluated in 18 healthy heifers. The animals were filmed before and after claw trimming while walking on a treadmill using high-speed cinematography (500 frames/s). For each limb, 4 consecutive steps were recorded from a side and a frontal plane. The objectives of the study were to evaluate 1) the order of claw contact with the treadmill surface, 2) the initial claw contact area, and 3) the effect of trimming on claw contact patterns. The heifers placed their front feet on the ground in a plane sagittal to the shoulders, whereas the hind feet were advanced more toward the median plane. Before trimming, the lateral claws contacted the ground before the medial in 83% of front and 100% of hind limbs. Trimming changed the percentage to 92% in the front and to 97% in the hind limbs. The percentage with which the heel of the lateral claws became the region of initial contact with the ground increased from 47 to 64% in the front feet and from 50 to 78% in the hind feet. In the medial claws of the forelimbs, claw trimming shifted the region of initial contact from the toe to the abaxial wall and heel. In the hind limbs, the main region of initial contact of the medial claws became the abaxial wall. Weight bearing by the medial claw became visibly apparent only during the midstance, propulsion, and push-off phases. "Heel first" contact of the lateral claws in the front and hind limbs may be the normal gait pattern in cattle. On hard surfaces, this pattern may lead to overload and predispose to disease, especially in the hind limbs. PMID:17235142

  18. Investigating Science through Bears (and Teddy Bears).

    ERIC Educational Resources Information Center

    Smith, Karlene Ray

    1997-01-01

    Presents cooperative classroom projects using science as the initial basis for the study of bears. These projects may also involve other areas of the curriculum such as mathematics, art, and music. "Black Bear" activities include following a park ranger to study our National Parks and researching and building a full-sized brown bear habitat. (AIM)

  19. ES and H-compatible lubrication for duplex bearings

    SciTech Connect

    Steinhoff, R.G.

    1997-10-01

    Two ES and H-compatible lubricants (environment, safety, and health) for duplex bearing applications and one hybrid material duplex bearing were evaluated and compared against duplex bearings with trichlorotrifluoroethane (Freon) deposition of low molecular weight polytetrafluoroethylene (PTFE) bearing lubricant extracted from Vydax{trademark}. Vydax is a product manufactured by DuPont consisting of various molecular weights of PTFE suspended in trichlorotrifluoroethane (Freon), which is an ozone-depleting solvent. Vydax has been used as a bearing lubricant in strong link mechanisms since 1974. Hybrid duplex bearings with silicon nitride balls and molded glass-nylon-Teflon retainers, duplex bearings lubricated with sputtered MoS{sub 2} on races and retainers, and duplex bearings lubricated with electrophoretic deposited MoS{sub 2} were evaluated. Bearings with electrophoretic deposited MoS{sub 2} performed as well as bearings with Freon deposition of PTFE from Freon-based Vydax. Hybrid bearings with silicon nitride balls performed worse than bearings lubricated with Vydax, but their performance would still be acceptable for most applications. Bearings lubricated with sputtered MoS{sub 2} on the races and retainers had varying amounts of film on the bearings. This affected the performance of the bearings. Bearings with a uniform coating performed to acceptable levels, but bearings with no visible MoS{sub 2} on the races and retainers did not perform as well as bearings with the other coatings. Unless process controls are incorporated in the sputtering process or the bearings are screened, they do not appear to be acceptable for duplex bearing applications.

  20. A simulator study of adverse wear with metal and cement debris contamination in metal-on-metal hip bearings

    PubMed Central

    Halim, T.; Clarke, I. C.; Burgett-Moreno, M. D.; Donaldson, T. K.; Savisaar, C.; Bowsher, J. G.

    2015-01-01

    Objectives Third-body wear is believed to be one trigger for adverse results with metal-on-metal (MOM) bearings. Impingement and subluxation may release metal particles from MOM replacements. We therefore challenged MOM bearings with relevant debris types of cobalt–chrome alloy (CoCr), titanium alloy (Ti6Al4V) and polymethylmethacrylate bone cement (PMMA). Methods Cement flakes (PMMA), CoCr and Ti6Al4V particles (size range 5 µm to 400 µm) were run in a MOM wear simulation. Debris allotments (5 mg) were inserted at ten intervals during the five million cycle (5 Mc) test. Results In a clean test phase (0 Mc to 0.8 Mc), lubricants retained their yellow colour. Addition of metal particles at 0.8 Mc turned lubricants black within the first hour of the test and remained so for the duration, while PMMA particles did not change the colour of the lubricant. Rates of wear with PMMA, CoCr and Ti6Al4V debris averaged 0.3 mm3/Mc, 4.1 mm3/Mc and 6.4 mm3/Mc, respectively. Conclusions Metal particles turned simulator lubricants black with rates of wear of MOM bearings an order of magnitude higher than with control PMMA particles. This appeared to model the findings of black, periarticular joint tissues and high CoCr wear in failed MOM replacements. The amount of wear debris produced during a 500 000-cycle interval of gait was 30 to 50 times greater than the weight of triggering particle allotment, indicating that MOM bearings were extremely sensitive to third-body wear. Cite this article: Bone Joint Res 2015;4:29–37. PMID:25736072

  1. Quantitative Gait Measurement With Pulse-Doppler Radar for Passive In-Home Gait Assessment

    PubMed Central

    Skubic, Marjorie; Rantz, Marilyn; Cuddihy, Paul E.

    2014-01-01

    In this paper, we propose a pulse-Doppler radar system for in-home gait assessment of older adults. A methodology has been developed to extract gait parameters including walking speed and step time using Doppler radar. The gait parameters have been validated with a Vicon motion capture system in the lab with 13 participants and 158 test runs. The study revealed that for an optimal step recognition and walking speed estimation, a dual radar set up with one radar placed at foot level and the other at torso level is necessary. An excellent absolute agreement with intraclass correlation coefficients of 0.97 was found for step time estimation with the foot level radar. For walking speed, although both radars show excellent consistency they all have a system offset compared to the ground truth due to walking direction with respect to the radar beam. The torso level radar has a better performance (9% offset on average) in the speed estimation compared to the foot level radar (13%–18% offset). Quantitative analysis has been performed to compute the angles causing the systematic error. These lab results demonstrate the capability of the system to be used as a daily gait assessment tool in home environments, useful for fall risk assessment and other health care applications. The system is currently being tested in an unstructured home environment. PMID:24771566

  2. Effects of gait training with horizontal impeding force on gait and balance of stroke patients.

    PubMed

    Na, Kyung-Pil; Kim, You Lim; Lee, Suk Min

    2015-03-01

    [Purpose] The purpose of this study was to investigate the effects of treadmill training with a horizontal impeding force applied to the center of upper body mass on the gait and balance of post-stroke patients. [Subjects and Methods] Twenty-four subjects with hemiplegia less than 3 months after stroke onset were randomly assigned to 2 groups: an applied horizontal impeding force on treadmill training (experimental) group (n = 12), and a control group (n = 12). Both groups walked on a treadmill at a comfortable or moderate speed for 20 minutes per day, 3 sessions per week for 8 weeks after a pre-test. The experimental group also had a horizontal impeding force applied to the center of their upper body mass. [Results] All groups demonstrated significant improvement after 8 weeks compared to baseline measurements. In intra-group comparisons, the subjects' gait ability (CGS, MGS, cadence, and step length) and balance ability (TUG, BBS, and FRT) significantly improved. In inter-group comparisons, the experimental group's improvement was significantly better in CGS MGS, cadence, step length, TUG, and BBS, but not in FRT. [Conclusion] Treadmill training was identified as an effective training method that improved gait and balance ability. A horizontal impeding force applied during treadmill training was more effective than treadmill walking training alone at improving the gait and dynamic balance of patients with stroke. PMID:25931719

  3. Effects of gait training with horizontal impeding force on gait and balance of stroke patients

    PubMed Central

    Na, Kyung-Pil; Kim, You Lim; Lee, Suk Min

    2015-01-01

    [Purpose] The purpose of this study was to investigate the effects of treadmill training with a horizontal impeding force applied to the center of upper body mass on the gait and balance of post-stroke patients. [Subjects and Methods] Twenty-four subjects with hemiplegia less than 3 months after stroke onset were randomly assigned to 2 groups: an applied horizontal impeding force on treadmill training (experimental) group (n = 12), and a control group (n = 12). Both groups walked on a treadmill at a comfortable or moderate speed for 20 minutes per day, 3 sessions per week for 8 weeks after a pre-test. The experimental group also had a horizontal impeding force applied to the center of their upper body mass. [Results] All groups demonstrated significant improvement after 8 weeks compared to baseline measurements. In intra-group comparisons, the subjects’ gait ability (CGS, MGS, cadence, and step length) and balance ability (TUG, BBS, and FRT) significantly improved. In inter-group comparisons, the experimental group’s improvement was significantly better in CGS MGS, cadence, step length, TUG, and BBS, but not in FRT. [Conclusion] Treadmill training was identified as an effective training method that improved gait and balance ability. A horizontal impeding force applied during treadmill training was more effective than treadmill walking training alone at improving the gait and dynamic balance of patients with stroke. PMID:25931719

  4. Quantitative gait measurement with pulse-Doppler radar for passive in-home gait assessment.

    PubMed

    Wang, Fang; Skubic, Marjorie; Rantz, Marilyn; Cuddihy, Paul E

    2014-09-01

    In this paper, we propose a pulse-Doppler radar system for in-home gait assessment of older adults. A methodology has been developed to extract gait parameters including walking speed and step time using Doppler radar. The gait parameters have been validated with a Vicon motion capture system in the lab with 13 participants and 158 test runs. The study revealed that for an optimal step recognition and walking speed estimation, a dual radar set up with one radar placed at foot level and the other at torso level is necessary. An excellent absolute agreement with intraclass correlation coefficients of 0.97 was found for step time estimation with the foot level radar. For walking speed, although both radars show excellent consistency they all have a system offset compared to the ground truth due to walking direction with respect to the radar beam. The torso level radar has a better performance (9% offset on average) in the speed estimation compared to the foot level radar (13%-18% offset). Quantitative analysis has been performed to compute the angles causing the systematic error. These lab results demonstrate the capability of the system to be used as a daily gait assessment tool in home environments, useful for fall risk assessment and other health care applications. The system is currently being tested in an unstructured home environment. PMID:24771566

  5. Lubricant replacement in rolling element bearings for weapon surety devices

    SciTech Connect

    Steinhoff, R.; Dugger, M.T.; Varga, K.S.

    1996-05-01

    Stronglink switches are a weapon surety device that is critical to the nuclear safety theme in modem nuclear weapons. These stronglink switches use rolling element bearings which contain a lubricant consisting of low molecular weight polytetrafluoroethylene (PTFE) fragments. Ozone-depleting solvents are used in both the manufacture and application of this lubricant. An alternate bearing lubrication for stronglink switches is needed that will provide long-term chemical stability, low migration and consistent performance. Candidates that were evaluated include bearings with sputtered MoS{sub 2} on the races and retainers, bearings with TiC-coated balls, and bearings with Si{sub 3}N{sub 4} balls and steel races. These candidates were compared to the lubricants currently used which are bearings lubricated with PTFE fragments of low molecular weight in a fluorocarbon solvent. The candidates were also compared to bearings lubricated with a diester oil which is representative of bearing lubricants used in industrial applications. Evaluation consisted of cycling preloaded bearings and subjecting them to 23 gRMS random vibration. All of the candidates are viable substitutes for low load application where bearing preload is approximately 1 pound. For high load applications where the bearing preload is approximately 10 pounds, bearings with sputtered MoS{sub 2} on the races and retainers appear to be the best substitutes. Bearings with TiC-coated balls also appear to be a viable candidate but these bearings did not perform as well as the sputtered MoS{sub 2}.

  6. Development of abnormal gait detection and vibratory stimulation system on lower limbs to improve gait stability.

    PubMed

    Yu, Mi; Piao, Yong-Jun; Eun, Hye-in; Kim, Dong-Wook; Ryu, Mun-ho; Kim, Nam-Gyun

    2010-10-01

    The purpose of this study is to develop an abnormal gait detection algorithm and a vibratory stimulation system on a lower limb to improve gait stability and prevent falls. The system consists of a gait measurement module, an abnormal gait detection module, and a vibratory stimulation module. The gait measurement module measures the vertical acceleration of the ankle during walking using an accelerometer. The measured acceleration values are sent to a portable microcontroller, which controls vibratory stimulations to the ankles based on an algorithm that detects the peak acceleration values. If the acceleration peaks are found to occur irregularly, the abnormal gait detection algorithm activates the vibratory stimulation module. To determine the effect of vibratory stimulations under dynamic condition, this study investigated the contribution of ankle muscle proprioception on the control of dynamic stability and lower limb kinematics while walking using vibratory stimulation to alter the muscle spindle output of individuals' left lower limb. Vibrators were attached to the left ankle joint (tibialis anterior, triceps surae). Participants were required to walk along a travel path and step over an obstacle placed in their way. There were four task conditions; an obstacle (10%, 20%, and 30% of the participants' height) was positioned at the midpoint of the walkway, or the participants' walking path remained clear. For each obstacle condition, participants experienced either no vibration, or vibration of the tibialis anterior muscle and the triceps surae muscle of the left lower limb. Vibration began upon detection of an abnormal gait and continued for one second. Vibrating the ankle muscles of the left lower limb while stepping over an obstacle resulted in significant changes in COM behavior on both the anterior/posterior (A/P) and medial/lateral (M/L) planes. The results provide strong evidence that the primary endings of the ankle muscle spindles play a significant role in the control of posture and balance during the swing phase of locomotion by providing information on the movement of the body's COM with respect to the support foot. PMID:20703630

  7. Novel actuation design of a gait trainer with shadow leg approach.

    PubMed

    Meuleman, Jos; Meuleman, Jos; van Asseldonk, Edwin H F; van der Kooij, Herman

    2013-06-01

    Robotic gait training has developed since the end of the 20(th) century, yet there is much room for improvement in the design of the robots. With the conventional exoskeleton structures, donning of patients in a gait trainer usually is a cumbersome process due to the need of joint alignments and normal walking is often hindered due to obstructed arm swing. Our goal was to design a gait training robots that overcomes these limitations. We propose a novel design in which these drawbacks are reduced to a great amount. By using a parallel structure behind the patient (shadow leg) that is connected to the patient joints with rods, little alignment is needed, the area lateral to the hip is left free, and thus arm swing is not obstructed. The construction is lightweight, because the actuators are mounted on a fixed base and the transmission of power is executed with light weight rods. An end stop in the shadow leg prevents hyper extension of the patient's knee. The relationship between motor displacement and human joint rotations is nonlinear. In this paper we derive the nonlinear relationships between motors and patient joints and verify these. calculations with a measurement. The device has been built, now tests with subjects are required to assess if subjects can indeed walk normally in the robot. PMID:24187188

  8. Inertial Sensor-Based Gait Recognition: A Review

    PubMed Central

    Sprager, Sebastijan; Juric, Matjaz B.

    2015-01-01

    With the recent development of microelectromechanical systems (MEMS), inertial sensors have become widely used in the research of wearable gait analysis due to several factors, such as being easy-to-use and low-cost. Considering the fact that each individual has a unique way of walking, inertial sensors can be applied to the problem of gait recognition where assessed gait can be interpreted as a biometric trait. Thus, inertial sensor-based gait recognition has a great potential to play an important role in many security-related applications. Since inertial sensors are included in smart devices that are nowadays present at every step, inertial sensor-based gait recognition has become very attractive and emerging field of research that has provided many interesting discoveries recently. This paper provides a thorough and systematic review of current state-of-the-art in this field of research. Review procedure has revealed that the latest advanced inertial sensor-based gait recognition approaches are able to sufficiently recognise the users when relying on inertial data obtained during gait by single commercially available smart device in controlled circumstances, including fixed placement and small variations in gait. Furthermore, these approaches have also revealed considerable breakthrough by realistic use in uncontrolled circumstances, showing great potential for their further development and wide applicability. PMID:26340634

  9. Inertial Sensor-Based Gait Recognition: A Review.

    PubMed

    Sprager, Sebastijan; Juric, Matjaz B

    2015-01-01

    With the recent development of microelectromechanical systems (MEMS), inertial sensors have become widely used in the research of wearable gait analysis due to several factors, such as being easy-to-use and low-cost. Considering the fact that each individual has a unique way of walking, inertial sensors can be applied to the problem of gait recognition where assessed gait can be interpreted as a biometric trait. Thus, inertial sensor-based gait recognition has a great potential to play an important role in many security-related applications. Since inertial sensors are included in smart devices that are nowadays present at every step, inertial sensor-based gait recognition has become very attractive and emerging field of research that has provided many interesting discoveries recently. This paper provides a thorough and systematic review of current state-of-the-art in this field of research. Review procedure has revealed that the latest advanced inertial sensor-based gait recognition approaches are able to sufficiently recognise the users when relying on inertial data obtained during gait by single commercially available smart device in controlled circumstances, including fixed placement and small variations in gait. Furthermore, these approaches have also revealed considerable breakthrough by realistic use in uncontrolled circumstances, showing great potential for their further development and wide applicability. PMID:26340634

  10. Instrumenting gait with an accelerometer: A system and algorithm examination

    PubMed Central

    Godfrey, A.; Del Din, S.; Barry, G.; Mathers, J.C.; Rochester, L.

    2015-01-01

    Gait is an important clinical assessment tool since changes in gait may reflect changes in general health. Measurement of gait is a complex process which has been restricted to the laboratory until relatively recently. The application of an inexpensive body worn sensor with appropriate gait algorithms (BWM) is an attractive alternative and offers the potential to assess gait in any setting. In this study we investigated the use of a low-cost BWM, compared to laboratory reference using a robust testing protocol in both younger and older adults. We observed that the BWM is a valid tool for estimating total step count and mean spatio-temporal gait characteristics however agreement for variability and asymmetry results was poor. We conducted a detailed investigation to explain the poor agreement between systems and determined it was due to inherent differences between the systems rather than inability of the sensor to measure the gait characteristics. The results highlight caution in the choice of reference system for validation studies. The BWM used in this study has the potential to gather longitudinal (real-world) spatio-temporal gait data that could be readily used in large lifestyle-based intervention studies, but further refinement of the algorithm(s) is required. PMID:25749552

  11. Carmen Martn Gaite and the Writing of History

    ERIC Educational Resources Information Center

    Herzberger, David K.

    2015-01-01

    In this brief article, David Herzberger begins by describing how, with the help of Juan Benet as her interlocutor in 1966, renowned Spanish author Carmen Martn Gaite found her historiographic voice. Herzberger goes on to examine how this relates to Martn Gaite's legacy in historiography and her understanding of the Franco regime and the Spanish

  12. DRAG: a database for recognition and analasys of gait

    NASA Astrophysics Data System (ADS)

    Kuchi, Prem; Hiremagalur, Raghu Ram V.; Huang, Helen; Carhart, Michael; He, Jiping; Panchanathan, Sethuraman

    2003-11-01

    A novel approach is proposed for creating a standardized and comprehensive database for gait analysis. The field of gait analysis is gaining increasing attention for applications such as visual surveillance, human-computer interfaces, and gait recognition and rehabilitation. Numerous algorithms have been developed for analyzing and processing gait data; however, a standard database for their systematic evaluation does not exist. Instead, existing gait databases consist of subsets of kinematic, kinetic, and electromyographic activity recordings by different investigators, at separate laboratories, and under varying conditions. Thus, the existing databases are neither homogenous nor sufficiently populated to statistically validate the algorithms. In this paper, a methodology for creating a database is presented, which can be used as a common ground to test the performance of algorithms that rely upon external marker data, ground reaction loading data, and/or video images. The database consists of: (1) synchronized motion-capture data (3D marker data) obtained using external markers, (2) computed joint angles, and (3) ground reaction loading acquired with plantar pressure insoles. This database could be easily expanded to include synchronized video, which will facilitate further development of video-based algorithms for motion tracking. This eventually could lead to the realization of markerless gait tracking. Such a system would have extensive applications in gait recognition, as well as gait rehabilitation. The entire database (marker, angle, and force data) will be placed in the public domain, and made available for downloads over the World Wide Web.

  13. Factors Related to Gait Function in Post-stroke Patients

    PubMed Central

    Cho, Ki Hun; Lee, Joo Young; Lee, Kun Jae; Kang, Eun Kyoung

    2014-01-01

    [Purpose] Gait function after a stroke is an important factor for determining a patient’s ability to independently perform activities of daily living (ADL). The objective of this study was to elucidate the factors associated with gait function in post-stroke patients. [Subjects] Thirty-nine stroke patients (16 females and 23 males; average age 67.82 ± 10.96 years; post-onset duration: 200.18 ± 27.14 days) participated in this study. [Methods] Their gait function, motor function (Manual Muscle Test [MMT] and Brünnstrom stage), level of cognition (Mini-Mental State Examination score [MMSE], and the Loewenstein Occupational Therapy Cognitive Assessment for the Geriatric Population [LOTCA-G]), and ADL (Korean modified Barthel index [K-MBI]) were assessed. [Results] The degree of gait function showed significant positive correlations with the following variables: MMT of the elbow, knee, ankle and wrist; Brünnstrom stage; MMSE; LOTCA-G subscores except motor praxis; K-MBI. Stepwise linear regression analysis revealed the Brünnstrom stage was the only explanatory variable closely associated with gait level. [Conclusion] Gait function of post-stroke patients was related to motor function, cognition, and ADL. In particular, there is a significant association between gait level and the Brünnstrom stages, reflecting the importance of monitoring the motor recovery of gait function in post-stroke patients. PMID:25540503

  14. Instrumenting gait with an accelerometer: a system and algorithm examination.

    PubMed

    Godfrey, A; Del Din, S; Barry, G; Mathers, J C; Rochester, L

    2015-04-01

    Gait is an important clinical assessment tool since changes in gait may reflect changes in general health. Measurement of gait is a complex process which has been restricted to the laboratory until relatively recently. The application of an inexpensive body worn sensor with appropriate gait algorithms (BWM) is an attractive alternative and offers the potential to assess gait in any setting. In this study we investigated the use of a low-cost BWM, compared to laboratory reference using a robust testing protocol in both younger and older adults. We observed that the BWM is a valid tool for estimating total step count and mean spatio-temporal gait characteristics however agreement for variability and asymmetry results was poor. We conducted a detailed investigation to explain the poor agreement between systems and determined it was due to inherent differences between the systems rather than inability of the sensor to measure the gait characteristics. The results highlight caution in the choice of reference system for validation studies. The BWM used in this study has the potential to gather longitudinal (real-world) spatio-temporal gait data that could be readily used in large lifestyle-based intervention studies, but further refinement of the algorithm(s) is required. PMID:25749552

  15. The Role of Executive Function and Attention in Gait

    PubMed Central

    Yogev, Galit; Hausdorff, Jeffrey M.; Giladi, Nir

    2008-01-01

    Until recently, gait was generally viewed as a largely automated motor task, requiring minimal higher-level cognitive input. Increasing evidence, however, links alterations in executive function and attention to gait disturbances. This review discusses the role of executive function and of attention in healthy walking and gait disorders while summarizing the relevant, recent literature. We describe the variety of gait disorders that may be associated with different aspects of executive function, and discuss the changes occurring in executive function as a result of aging and disease as well the potential impact of these changes on gait. The attentional demands of gait are often tested using dual tasking methodologies. Relevant studies in healthy adults and patients are presented, as are the possible mechanisms responsible for the deterioration of gait during dual tasking. Lastly, we suggest how assessments of executive function and attention could be applied in the clinical setting as part of the process of identifying and understanding gait disorders and fall risk. PMID:18058946

  16. Comparative gait analysis between children with autism and age-matched controls: analysis with temporal-spatial and foot pressure variables

    PubMed Central

    Lim, Bee-Oh; O’Sullivan, David; Choi, Bum-Gwon; Kim, Mi-Young

    2016-01-01

    [Purpose] The purpose of this study was to investigate the gait pattern of children with autism by using a gait analysis system. [Subjects] Thirty children were selected for this study: 15 with autism (age, 11.2 ± 2.8 years; weight, 48.1 ± 14.1 kg; height, 1.51 ± 0.11 m) and 15 healthy age-matched controls (age, 11.0 ± 2.9 years; weight, 43.6 ± 10 kg; height, 1.51 ± 0.011 m). [Methods] All participants walked three times on the GAITRite® system while their plantar pressure was being recorded. [Results] The results showed a reduction in cadence, gait velocity, and step length, and an increase in step width in children with autism. Plantar pressure variables highlight the differences between the active pressure areas, especially in the hindfoot of children with autism. [Conclusion] The results suggest that children with autism have an abnormal gait compared with that of age-matched controls, and thus they need extra attention to correct these abnormal gait patterns. PMID:26957776

  17. Is adult gait less susceptible than paediatric gait to hip joint centre regression equation error?

    PubMed

    Kiernan, D; Hosking, J; O'Brien, T

    2016-03-01

    Hip joint centre (HJC) regression equation error during paediatric gait has recently been shown to have clinical significance. In relation to adult gait, it has been inferred that comparable errors with children in absolute HJC position may in fact result in less significant kinematic and kinetic error. This study investigated the clinical agreement of three commonly used regression equation sets (Bell et al., Davis et al. and Orthotrak) for adult subjects against the equations of Harrington et al. The relationship between HJC position error and subject size was also investigated for the Davis et al. set. Full 3-dimensional gait analysis was performed on 12 healthy adult subjects with data for each set compared to Harrington et al. The Gait Profile Score, Gait Variable Score and GDI-kinetic were used to assess clinical significance while differences in HJC position between the Davis and Harrington sets were compared to leg length and subject height using regression analysis. A number of statistically significant differences were present in absolute HJC position. However, all sets fell below the clinically significant thresholds (GPS <1.6°, GDI-Kinetic <3.6 points). Linear regression revealed a statistically significant relationship for both increasing leg length and increasing subject height with decreasing error in anterior/posterior and superior/inferior directions. Results confirm a negligible clinical error for adult subjects suggesting that any of the examined sets could be used interchangeably. Decreasing error with both increasing leg length and increasing subject height suggests that the Davis set should be used cautiously on smaller subjects. PMID:26979895

  18. Design and test of a magnetic thrust bearing

    NASA Technical Reports Server (NTRS)

    Allaire, P. E.; Mikula, A.; Banerjee, B.; Lewis, D. W.; Imlach, J.

    1993-01-01

    A magnetic thrust bearing can be employed to take thrust loads in rotating machinery. The design and construction of a prototype magnetic thrust bearing for a high load per weight application is described. The theory for the bearing is developed. Fixtures were designed and the bearing was tested for load capacity using a universal testing machine. Various shims were employed to have known gap thicknesses. A comparison of the theory and measured results is presented.

  19. Optimality Principles for Model-Based Prediction of Human Gait

    PubMed Central

    Ackermann, Marko; van den Bogert, Antonie J.

    2010-01-01

    Although humans have a large repertoire of potential movements, gait patterns tend to be stereotypical and appear to be selected according to optimality principles such as minimal energy. When applied to dynamic musculoskeletal models such optimality principles might be used to predict how a patient’s gait adapts to mechanical interventions such as prosthetic devices or surgery. In this paper we study the effects of different performance criteria on predicted gait patterns using a 2D musculoskeletal model. The associated optimal control problem for a family of different cost functions was solved utilizing the direct collocation method. It was found that fatigue-like cost functions produced realistic gait, with stance phase knee flexion, as opposed to energy-related cost functions which avoided knee flexion during the stance phase. We conclude that fatigue minimization may be one of the primary optimality principles governing human gait. PMID:20074736

  20. A Grassmann graph embedding framework for gait analysis

    NASA Astrophysics Data System (ADS)

    Connie, Tee; Goh, Michael Kah Ong; Teoh, Andrew Beng Jin

    2014-12-01

    Gait recognition is important in a wide range of monitoring and surveillance applications. Gait information has often been used as evidence when other biometrics is indiscernible in the surveillance footage. Building on recent advances of the subspace-based approaches, we consider the problem of gait recognition on the Grassmann manifold. We show that by embedding the manifold into reproducing kernel Hilbert space and applying the mechanics of graph embedding on such manifold, significant performance improvement can be obtained. In this work, the gait recognition problem is studied in a unified way applicable for both supervised and unsupervised configurations. Sparse representation is further incorporated in the learning mechanism to adaptively harness the local structure of the data. Experiments demonstrate that the proposed method can tolerate variations in appearance for gait identification effectively.

  1. Summary measures for clinical gait analysis: a literature review.

    PubMed

    Cimolin, Veronica; Galli, Manuela

    2014-04-01

    Instrumented 3D-gait analysis (3D-GA) is an important method used to obtain information that is crucial for establishing the level of functional limitation due to pathology, observing its evolution over time and evaluating rehabilitative intervention effects. However, a typical 3D-GA evaluation produces a vast amount of data, and despite its objectivity, its use is complicated, and the data interpretation is difficult. It is even more difficult to obtain an overview on patient cohorts for a comparison. Moreover, there is a growing awareness of the need for a concise index, specifically, a single measure of the 'quality' of a particular gait pattern. Several gait summary measures, which have been used in conjunction with 3D-GA, have been proposed to objectify clinical impression, quantify the degree of gait deviation from normal, stratify the severity of pathology, document the changes in gait patterns over time and evaluate interventions. PMID:24613461

  2. Optimality principles for model-based prediction of human gait.

    PubMed

    Ackermann, Marko; van den Bogert, Antonie J

    2010-04-19

    Although humans have a large repertoire of potential movements, gait patterns tend to be stereotypical and appear to be selected according to optimality principles such as minimal energy. When applied to dynamic musculoskeletal models such optimality principles might be used to predict how a patient's gait adapts to mechanical interventions such as prosthetic devices or surgery. In this paper we study the effects of different performance criteria on predicted gait patterns using a 2D musculoskeletal model. The associated optimal control problem for a family of different cost functions was solved utilizing the direct collocation method. It was found that fatigue-like cost functions produced realistic gait, with stance phase knee flexion, as opposed to energy-related cost functions which avoided knee flexion during the stance phase. We conclude that fatigue minimization may be one of the primary optimality principles governing human gait. PMID:20074736

  3. Gait Analysis Methods for Rodent Models of Osteoarthritis

    PubMed Central

    Jacobs, Brittany Y.; Kloefkorn, Heidi E.; Allen, Kyle D.

    2014-01-01

    Patients with osteoarthritis (OA) primarily seek treatment due to pain and disability, yet the primary endpoints for rodent OA models tend to be histological measures of joint destruction. The discrepancy between clinical and preclinical evaluations is problematic, given that radiographic evidence of OA in humans does not always correlate to the severity of patient-reported symptoms. Recent advances in behavioral analyses have provided new methods to evaluate disease sequelae in rodents. Of particular relevance to rodent OA models are methods to assess rodent gait. While obvious differences exist between quadrupedal and bipedal gait sequences, the gait abnormalities seen in humans and in rodent OA models reflect similar compensatory behaviors that protect an injured limb from loading. The purpose of this review is to describe these compensations and current methods used to assess rodent gait characteristics, while detailing important considerations for the selection of gait analysis methods in rodent OA models. PMID:25160712

  4. Powered lower limb orthoses for gait rehabilitation

    PubMed Central

    Ferris, Daniel P.; Sawicki, Gregory S.; Domingo, Antoinette

    2006-01-01

    Bodyweight supported treadmill training has become a prominent gait rehabilitation method in leading rehabilitation centers. This type of locomotor training has many functional benefits but the labor costs are considerable. To reduce therapist effort, several groups have developed large robotic devices for assisting treadmill stepping. A complementary approach that has not been adequately explored is to use powered lower limb orthoses for locomotor training. Recent advances in robotic technology have made lightweight powered orthoses feasible and practical. An advantage to using powered orthoses as rehabilitation aids is they allow practice starting, turning, stopping, and avoiding obstacles during overground walking. PMID:16568153

  5. A novel shear reduction insole effect on the thermal response to walking stress, balance, and gait.

    PubMed

    Wrobel, James S; Ammanath, Peethambaran; Le, Tima; Luring, Christopher; Wensman, Jeffrey; Grewal, Gurtej S; Najafi, Bijan; Pop-Busui, Rodica

    2014-11-01

    Shear stresses have been implicated in the formation of diabetes-related foot ulcers. The aim of this study was to evaluate the effect of a novel shear-reducing insole on the thermal response to walking, balance, and gait. Twenty-seven diabetes peripheral neuropathy patients were enrolled and asked to take 200 steps in both intervention and standard insoles. Thermal foot images of the feet were taken at baseline (1) following a 5-minute temperature acclimatization and (2) after walking. Testing order was randomized, and a 5-minute washout period was used between testing each insole condition. Sudomotor function was also assessed. Gait and balance were measured under single and dual task conditions using a validated body worn sensor system. The mean age was 65.1 years, height was 67.3 inches, weight was 218 pounds, and body mass index was 33.9, 48% were female, and 82% had type 2 diabetes. After walking in both insole conditions, foot temperatures increased significantly in standard insoles. The intervention insole significantly reduced forefoot and midfoot temperature increases (64.1%, P = .008; 48%, P = .046) compared to standard insoles. There were significant negative correlations with sudomotor function and baseline temperatures (r = .53-.57). The intervention demonstrated 10.4% less gait initiation double support time compared to standard insoles (P = .05). There were no differences in static balance measures. We found significantly lower forefoot and midfoot temperature increases following walking with shear-reducing insoles compared to standard insoles. We also found improvements in gait. These findings merit future study for the prevention of foot ulcer. PMID:25107709

  6. A Novel Shear Reduction Insole Effect on the Thermal Response to Walking Stress, Balance, and Gait

    PubMed Central

    Ammanath, Peethambaran; Le, Tima; Luring, Christopher; Wensman, Jeffrey; Grewal, Gurtej S.; Najafi, Bijan; Pop-Busui, Rodica

    2014-01-01

    Shear stresses have been implicated in the formation of diabetes-related foot ulcers. The aim of this study was to evaluate the effect of a novel shear-reducing insole on the thermal response to walking, balance, and gait. Twenty-seven diabetes peripheral neuropathy patients were enrolled and asked to take 200 steps in both intervention and standard insoles. Thermal foot images of the feet were taken at baseline (1) following a 5-minute temperature acclimatization and (2) after walking. Testing order was randomized, and a 5-minute washout period was used between testing each insole condition. Sudomotor function was also assessed. Gait and balance were measured under single and dual task conditions using a validated body worn sensor system. The mean age was 65.1 years, height was 67.3 inches, weight was 218 pounds, and body mass index was 33.9, 48% were female, and 82% had type 2 diabetes. After walking in both insole conditions, foot temperatures increased significantly in standard insoles. The intervention insole significantly reduced forefoot and midfoot temperature increases (64.1%, P = .008; 48%, P = .046) compared to standard insoles. There were significant negative correlations with sudomotor function and baseline temperatures (r = .53-.57). The intervention demonstrated 10.4% less gait initiation double support time compared to standard insoles (P = .05). There were no differences in static balance measures. We found significantly lower forefoot and midfoot temperature increases following walking with shear-reducing insoles compared to standard insoles. We also found improvements in gait. These findings merit future study for the prevention of foot ulcer. PMID:25107709

  7. Gait Transitions in Human Infants: Coping with Extremes of Treadmill Speed

    PubMed Central

    Vasudevan, Erin V.; Patrick, Susan K.; Yang, Jaynie F.

    2016-01-01

    Spinal pattern generators in quadrupedal animals can coordinate different forms of locomotion, like trotting or galloping, by altering coordination between the limbs (interlimb coordination). In the human system, infants have been used to study the subcortical control of gait, since the cerebral cortex and corticospinal tract are immature early in life. Like other animals, human infants can modify interlimb coordination to jump or step. Do human infants possess functional neuronal circuitry necessary to modify coordination within a limb (intralimb coordination) in order to generate distinct forms of alternating bipedal gait, such as walking and running? We monitored twenty-eight infants (7–12 months) stepping on a treadmill at speeds ranging between 0.06–2.36 m/s, and seventeen adults (22–47 years) walking or running at speeds spanning the walk-to-run transition. Six of the adults were tested with body weight support to mimic the conditions of infant stepping. We found that infants could accommodate a wide range of speeds by altering stride length and frequency, similar to adults. Moreover, as the treadmill speed increased, we observed periods of flight during which neither foot was in ground contact in infants and in adults. However, while adults modified other aspects of intralimb coordination and the mechanics of progression to transition to a running gait, infants did not make comparable changes. The lack of evidence for distinct walking and running patterns in infants suggests that the expression of different functional, alternating gait patterns in humans may require neuromuscular maturation and a period of learning post-independent walking. PMID:26828941

  8. Carrying shopping bags does not alter static postural stability and gait parameters in healthy older females.

    PubMed

    Bampouras, Theodoros M; Dewhurst, Susan

    2016-05-01

    Food shopping is an important aspect of maintaining independence and social interaction in older age. Carriage of shopping bags alters the body's weight distribution which, depending on load distribution, could potentially increase instability during standing and walking. The study examined the effect of carrying UK style shopping bags on static postural stability and gait in healthy older and young females. Nine older (71.0±6.0 years) and 10 young (26.7±5.2 years) females were assessed in five conditions carrying no bags, one 1.5kg bag in each hand, one 3kg bag in each hand, one 1.5kg bag in preferred hand, one 3kg bag in preferred hand. Antero-posterior and medio-lateral displacement, and 95% ellipse area from a 30s quiet standing were used for postural stability assessment. Stride length and its coefficient of variation, total double support time, step asymmetry and gait stability ratio were calculated from 1min treadmill walking at self-selected speed for gait assessment. Carrying shopping bags did not negatively affect postural stability or gait variables, in either group. Further, in older individuals, a decrease in sway velocity was found when holding bags during the postural stability assessment (p<0.05), suggesting that carriage of bags, irrespective of the load distribution, may have a stabilising effect during quiet standing. These results should help to alleviate concerns regarding safety of carrying shopping bags and help encourage shopping, both as a social and as a physical activity. PMID:27131182

  9. Overground robot assisted gait trainer for the treatment of drug-resistant freezing of gait in Parkinson disease.

    PubMed

    Pilleri, Manuela; Weis, Luca; Zabeo, Letizia; Koutsikos, Konstantinos; Biundo, Roberta; Facchini, Silvia; Rossi, Simonetta; Masiero, Stefano; Antonini, Angelo

    2015-08-15

    Freezing of Gait (FOG) is a frequent and disabling feature of Parkinson disease (PD). Gait rehabilitation assisted by electromechanical devices, such as training on treadmill associated with sensory cues or assisted by gait orthosis have been shown to improve FOG. Overground robot assisted gait training (RGT) has been recently tested in patients with PD with improvement of several gait parameters. We here evaluated the effectiveness of RGT on FOG severity and gait abnormalities in PD patients. Eighteen patients with FOG resistant to dopaminergic medications were treated with 15 sessions of RGT and underwent an extensive clinical evaluation before and after treatment. The main outcome measures were FOG questionnaire (FOGQ) global score and specific tasks for gait assessment, namely 10 meter walking test (10 MWT), Timed Up and Go test (TUG) and 360° narrow turns (360 NT). Balance was also evaluated through Fear of Falling Efficacy Scale (FFES), assessing self perceived stability and Berg Balance Scale (BBS), for objective examination. After treatment, FOGQ score was significantly reduced (P=0.023). We also found a significant reduction of time needed to complete TUG, 10 MWT, and 360 NT (P=0.009, 0.004 and 0.04, respectively). By contrast the number of steps and the number of freezing episodes recorded at each gait task did not change. FFES and BBS scores also improved, with positive repercussions on performance on daily activity and quality of life. Our results indicate that RGT is a useful strategy for the treatment of drug refractory FOG. PMID:26048047

  10. DMRT3 is associated with gait type in Mangalarga Marchador horses, but does not control gait ability.

    PubMed

    Patterson, L; Staiger, E A; Brooks, S A

    2015-04-01

    The Mangalarga Marchador (MM) is a Brazilian horse breed known for a uniquely smooth gait. A recent publication described a mutation in the DMRT3 gene that the authors claim controls the ability to perform lateral patterned gaits (Andersson et al. 2012). We tested 81 MM samples for the DMRT3 mutation using extracted DNA from hair bulbs using a novel RFLP. Horses were phenotypically categorized by their gait type (batida or picada), as recorded by the Brazilian Mangalarga Marchador Breeders Association (ABCCMM). Statistical analysis using the plink toolset (Purcell, 2007) revealed significant association between gait type and the DMRT3 mutation (P = 2.3e-22). Deviation from Hardy-Weinberg equilibrium suggests that selective pressure for gait type is altering allele frequencies in this breed (P = 1.00e-5). These results indicate that this polymorphism may be useful for genotype-assisted selection for gait type within this breed. As both batida and picada MM horses can perform lateral gaits, the DMRT3 mutation is not the only locus responsible for the lateral gait pattern. PMID:25690906

  11. Restoration of bearings

    NASA Technical Reports Server (NTRS)

    Parker, R. J.; Zaretsky, E. V.; Hanau, H.

    1977-01-01

    Process consisting of grinding raceways to oversize but original quality condition and installing new oversize balls or bearings restores wornout ball and roller bearings to original quality, thereby doubling their operating life. Evaluations reveal process results in restoration of 90% of replaced bearings at less than 50% of new-bearing costs.

  12. Passive magnetic bearing configurations

    DOEpatents

    Post, Richard F.

    2011-01-25

    A journal bearing provides vertical and radial stability to a rotor of a passive magnetic bearing system when the rotor is not rotating and when it is rotating. In the passive magnetic bearing system, the rotor has a vertical axis of rotation. Without the journal bearing, the rotor is vertically and radially unstable when stationary, and is vertically stable and radially unstable when rotating.

  13. Rolling-Element Bearings

    NASA Technical Reports Server (NTRS)

    Hamrock, B. J.; Anderson, W. J.

    1983-01-01

    Rolling element bearings are a precision, yet simple, machine element of great utility. A brief history of rolling element bearings is reviewed and the type of rolling element bearings, their geometry and kinematics, as well as the materials they are made from and the manufacturing processes they involve are described. Unloaded and unlubricated rolling element bearings, loaded but unlubricated rolling element bearings and loaded and lubricated rolling element bearings are considered. The recognition and understanding of elastohydrodynamic lubrication covered, represents one of the major development in rolling element bearings.

  14. Introduction to ball bearings

    NASA Technical Reports Server (NTRS)

    Hamrock, B. J.; Dowson, D.

    1981-01-01

    The purpose of a ball bearing is to provide a relative positioning and rotational freedom while transmitting a load between two structures, usually a shaft and a housing. For high rotational speeds (e.g., in gyroscope ball bearings) the purpose can be expanded to include rotational freedom with practically no wear in the bearing. This condition can be achieved by separating the bearing parts with a coherent film of fluid known as an elastohydrodynamic film. This film can be maintained not only when the bearing carries the load on a shaft, but also when the bearing is preloaded to position the shaft to within micro- or nano-inch accuracy and stability. Background information on ball bearings is provided, different types of ball bearings and their geometry and kinematics are defined, bearing materials, manufacturing processes, and separators are discussed. It is assumed, for the purposes of analysis, that the bearing carries no load.

  15. High efficiency magnetic bearings

    NASA Technical Reports Server (NTRS)

    Studer, Philip A.; Jayaraman, Chaitanya P.; Anand, Davinder K.; Kirk, James A.

    1993-01-01

    Research activities concerning high efficiency permanent magnet plus electromagnet (PM/EM) pancake magnetic bearings at the University of Maryland are reported. A description of the construction and working of the magnetic bearing is provided. Next, parameters needed to describe the bearing are explained. Then, methods developed for the design and testing of magnetic bearings are summarized. Finally, a new magnetic bearing which allows active torque control in the off axes directions is discussed.

  16. Gait Patterns in Twins with Cerebral Palsy: Similarities and Development over Time after Multilevel Surgery

    ERIC Educational Resources Information Center

    van Drongelen, Stefan; Dreher, Thomas; Heitzmann, Daniel W. W.; Wolf, Sebastian I.

    2013-01-01

    To examine gait patterns and gait quality, 7 twins with cerebral palsy were measured preoperatively and after surgical intervention. The aim was to study differences and/or similarities in gait between twins, the influence of personal characteristics and birth conditions, and to describe the development of gait over time after single event

  17. Probabilistic Gait Classification in Children with Cerebral Palsy: A Bayesian Approach

    ERIC Educational Resources Information Center

    Van Gestel, Leen; De Laet, Tinne; Di Lello, Enrico; Bruyninckx, Herman; Molenaers, Guy; Van Campenhout, Anja; Aertbelien, Erwin; Schwartz, Mike; Wambacq, Hans; De Cock, Paul; Desloovere, Kaat

    2011-01-01

    Three-dimensional gait analysis (3DGA) generates a wealth of highly variable data. Gait classifications help to reduce, simplify and interpret this vast amount of 3DGA data and thereby assist and facilitate clinical decision making in the treatment of CP. CP gait is often a mix of several clinically accepted distinct gait patterns. Therefore,

  18. Gait Patterns in Hemiplegic Children with Cerebral Palsy: Comparison of Right and Left Hemiplegia

    ERIC Educational Resources Information Center

    Galli, Manuela; Cimolin, Veronica; Rigoldi, Chiara; Tenore, Nunzio; Albertini, Giorgio

    2010-01-01

    The aims of this study are to compare quantitatively the gait strategy of the right and left hemiplegic children with Cerebral Palsy (CP) using gait analysis. The gait strategy of 28 right hemiparetic CP (RHG) and 23 left hemiparetic CP (LHG) was compared using gait analysis (spatio-temporal and kinematic parameters) and considering the hemiplegic

  19. Gait Patterns in Hemiplegic Children with Cerebral Palsy: Comparison of Right and Left Hemiplegia

    ERIC Educational Resources Information Center

    Galli, Manuela; Cimolin, Veronica; Rigoldi, Chiara; Tenore, Nunzio; Albertini, Giorgio

    2010-01-01

    The aims of this study are to compare quantitatively the gait strategy of the right and left hemiplegic children with Cerebral Palsy (CP) using gait analysis. The gait strategy of 28 right hemiparetic CP (RHG) and 23 left hemiparetic CP (LHG) was compared using gait analysis (spatio-temporal and kinematic parameters) and considering the hemiplegic…

  20. Probabilistic Gait Classification in Children with Cerebral Palsy: A Bayesian Approach

    ERIC Educational Resources Information Center

    Van Gestel, Leen; De Laet, Tinne; Di Lello, Enrico; Bruyninckx, Herman; Molenaers, Guy; Van Campenhout, Anja; Aertbelien, Erwin; Schwartz, Mike; Wambacq, Hans; De Cock, Paul; Desloovere, Kaat

    2011-01-01

    Three-dimensional gait analysis (3DGA) generates a wealth of highly variable data. Gait classifications help to reduce, simplify and interpret this vast amount of 3DGA data and thereby assist and facilitate clinical decision making in the treatment of CP. CP gait is often a mix of several clinically accepted distinct gait patterns. Therefore,…

  1. Gait Patterns in Twins with Cerebral Palsy: Similarities and Development over Time after Multilevel Surgery

    ERIC Educational Resources Information Center

    van Drongelen, Stefan; Dreher, Thomas; Heitzmann, Daniel W. W.; Wolf, Sebastian I.

    2013-01-01

    To examine gait patterns and gait quality, 7 twins with cerebral palsy were measured preoperatively and after surgical intervention. The aim was to study differences and/or similarities in gait between twins, the influence of personal characteristics and birth conditions, and to describe the development of gait over time after single event…

  2. A synergetic model for human gait transitions

    NASA Astrophysics Data System (ADS)

    Abdolvahab, Mohammad

    2015-09-01

    Gait transitions have been considered as bifurcations between states (e.g. walking or running modes) of a nonlinear dynamical system. A top-down synergetic approach to model gait transitions has been adapted from Frank et al. (2009) and applied to two sets of empirical observations. In this approach, it is assumed that the amplitudes of the spatio-temporal modes of locomotion satisfy a generic form of evolution equations that are known to hold for animate and inanimate self-organizing systems. The presented experimental results focus on hysteresis in human walk-to-run and run-to-walk transitions on a treadmill as a function of treadmill inclination and acceleration, the rate at which speed was increased or decreased during experimental trials. The bi-stability in the synergetic model is assumed to account for the hysteretic transitions. Accordingly, the relevant parameters of the model were estimated from the empirical data and the model's efficacy in predicting the observed hysteresis effects was evaluated.

  3. Functional MRI in the assessment of cortical activation during gait-related imaginary tasks.

    PubMed

    Wang, JiunJie; Wai, YauYau; Weng, YiHsin; Ng, KoonKwan; Huang, Ying-Zu; Ying, Leslie; Liu, HaoLi; Wang, ChiHong

    2009-09-01

    Imaginary tasks can be used to investigate the neurophysiology of gait. In this study, we explored the cortical control of gait-related imagery in 21 healthy volunteers using functional magnetic resonance imaging. Imaginary tasks included gait initiation, stepping over an obstacle, and gait termination. Subjects watched a video clip that showed an actor in gait motion under an event-related design. We detected activation in the supplementary motor area during major gait-related imagery tasks, and especially during gait initiation. During gait termination and stepping over an obstacle, the amount of cortical resources allocated to the imaginary tasks included a large visuomotor network comprising the dorsal and ventral premotor areas. We conclude that our paradigm to study the cortical control of gait may help in elucidating the pathophysiology of higher-level gait disorders. PMID:19669694

  4. Gait analysis parameters of healthy human subjects with asymmetric loads.

    PubMed

    Berceanu, C; Marghitu, D B; Gudavalli, M R; Raju, P K; Vikas, Y

    2016-06-01

    This article focuses on the analysis of gait parameters, ground reaction forces (GRF), and motion signals, for the various asymmetric loads carried by healthy human subjects during walking. Eight asymptomatic human volunteers were enrolled in this study. They were asked to walk, at self-selected pace, with various weights ranging from 0 to 11.33 kg (25 lbs) in 2.26 kg (5 lbs) increments, in one hand on a wooden area equipped with a force platform. Moreover, motion data were recorded from lumbar L1 vertebrae at a frequency of 120 Hz. Three trials of data have been recorded for each subject. In order to quantify the effect of increasing loads on the GRF we define the compression area, restitution area, and coefficient of restitution (COR) for GRF curves. We observe an increase in the compression area with respect to the load and almost constant values for the COR. For motion signals analysis we employ wavelet theory. The signals obtained from the lumbar L1 sensor of the spine vertebrae show a decrease in the wavelet detail energy, for the levels 3, 4, and 5, with respect to increasing loads. PMID:26274771

  5. Assessment of gait after bilateral hip replacement. Case study.

    PubMed

    Winiarski, Sławomir; Aleksandrowicz, Krzysztof; Jarząb, Sławomir; Pozowski, Andrzej; Rutkowska-Kucharska, Alicja

    2014-01-01

    Total hip arthroplasty (THA) is one of the most effective methods of treatment of severe hip osteoarthritis (HOA). In many cases pathological gait patterns persist despite properly conducted surgery and disturb the normal wear of the artificial joint surfaces. The aim of the study was to conduct functional and biomechanical assessment of gait in a patient after bilateral THA due to severe degenerative changes in the hip. The assessment focused on the gait parameters which significantly deviate from a normal gait pattern at various stages of treatment. Physiotherapeutic assessment of the patient included measurements of the range of motion in lower limb joints, the Timed Up and Go test, and pain assessment. Biomechanical assessment involved measurements of spatiotemporal gait parameters and the dynamic range of motion using BTS Smart-E motion analysis system. Although clinical examinations after both the first and second procedure suggested recovery of the patient's physical function, biomechanical assessment of her gait after the second procedure indicated the presence of deviations from a normal gait pattern. Secondary to a limited range of internal/external hip rotation, extension, and abduction, corresponding indices were still in the pathological range. PMID:25041890

  6. The effect of branch diameter on primate gait sequence pattern.

    PubMed

    Stevens, Nancy Jeanne

    2008-04-01

    Most mammals use lateral sequence gaits during quadrupedal locomotion, a pattern characterized by the touchdown of a forelimb directly following the ipsilateral hind limb in a given stride cycle. Primates, however, tend to use diagonal sequence (DS) gaits, whereby it is the touchdown of a contralateral forelimb that follows that of a given hind limb most closely in time. A number of scenarios have been offered to explain why primates favor DS gaits, most of them relating to the use of the arboreal habitat and, in particular, the exploitation of a narrow branch niche. This experimental study explores the potential explanation for the use of DS gaits by examining the relationship between branch diameter and gait patterns in 360 strides collected from six species of quadrupedal strepsirrhine primates on broad and narrow diameter supports. Gait sequence is quantified using limb phase, or the percentage of time during a stride cycle that a forelimb touchdown follows an ipsilateral hind limb touchdown. Although Loris, Nycticebus and Eulemur rubriventer individuals in this study did exhibit significantly lower locomotor velocities on narrower supports (P<0.01 in all three species), analyses of covariance showed no significant differences in limb phase values between broad and narrow diameter supports. Hence, results indicate surprisingly little evidence to suggest that alterations in gait sequence pattern provide a specific advantage for negotiating narrow supports. PMID:17972283

  7. Turtle mimetic soft robot with two swimming gaits.

    PubMed

    Song, Sung-Hyuk; Kim, Min-Soo; Rodrigue, Hugo; Lee, Jang-Yeob; Shim, Jae-Eul; Kim, Min-Cheol; Chu, Won-Shik; Ahn, Sung-Hoon

    2016-01-01

    This paper presents a biomimetic turtle flipper actuator consisting of a shape memory alloy composite structure for implementation in a turtle-inspired autonomous underwater vehicle. Based on the analysis of the Chelonia mydas, the flipper actuator was divided into three segments containing a scaffold structure fabricated using a 3D printer. According to the filament stacking sequence of the scaffold structure in the actuator, different actuating motions can be realized and three different types of scaffold structures were proposed to replicate the motion of the different segments of the flipper of the Chelonia mydas. This flipper actuator can mimic the continuous deformation of the forelimb of Chelonia mydas which could not be realized in previous motor based robot. This actuator can also produce two distinct motions that correspond to the two different swimming gaits of the Chelonia mydas, which are the routine and vigorous swimming gaits, by changing the applied current sequence of the SMA wires embedded in the flipper actuator. The generated thrust and the swimming efficiency in each swimming gait of the flipper actuator were measured and the results show that the vigorous gait has a higher thrust but a relatively lower swimming efficiency than the routine gait. The flipper actuator was implemented in a biomimetic turtle robot, and its average swimming speed in the routine and vigorous gaits were measured with the vigorous gait being capable of reaching a maximum speed of 11.5 mm s(-1). PMID:27145061

  8. Gait biometrics under spoofing attacks: an experimental investigation

    NASA Astrophysics Data System (ADS)

    Hadid, Abdenour; Ghahramani, Mohammad; Kellokumpu, Vili; Feng, Xiaoyi; Bustard, John; Nixon, Mark

    2015-11-01

    Gait is a relatively biometric modality which has a precious advantage over other modalities, such as iris and voice, in that it can be easily captured from a distance. Although it has recently become a topic of great interest in biometric research, there has been little investigation into gait spoofing attacks where a person tries to imitate the clothing or walking style of someone else. We recently analyzed for the first time the effects of spoofing attacks on silhouette-based gait biometric systems and showed that it was indeed possible to spoof gait biometric systems by clothing impersonation and the deliberate selection of a target that has a similar build to the attacker. To gain deeper insight into the performance of current gait biometric systems under spoofing attacks, we provide a thorough investigation on how clothing can be used to spoof a target and evaluate the performance of two state-of-the-art recognition methods on a gait spoofing database recorded at the University of Southampton. Furthermore, we describe and evaluate an initial solution coping with gait spoofing attacks. The obtained results are very promising and point out interesting findings which can be used for future investigations.

  9. Computational evaluation of load carriage effects on gait balance stability.

    PubMed

    Mummolo, Carlotta; Park, Sukyung; Mangialardi, Luigi; Kim, Joo H

    2016-08-01

    Evaluating the effects of load carriage on gait balance stability is important in various applications. However, their quantification has not been rigorously addressed in the current literature, partially due to the lack of relevant computational indices. The novel Dynamic Gait Measure (DGM) characterizes gait balance stability by quantifying the relative effects of inertia in terms of zero-moment point, ground projection of center of mass, and time-varying foot support region. In this study, the DGM is formulated in terms of the gait parameters that explicitly reflect the gait strategy of a given walking pattern and is used for computational evaluation of the distinct balance stability of loaded walking. The observed gait adaptations caused by load carriage (decreased single support duration, inertia effects, and step length) result in decreased DGM values (p < 0.0001), which indicate that loaded walking motions are more statically stable compared with the unloaded normal walking. Comparison of the DGM with other common gait stability indices (the maximum Floquet multiplier and the margin of stability) validates the unique characterization capability of the DGM, which is consistently informative of the presence of the added load. PMID:26691823

  10. Understanding gait control in post-stroke: implications for management.

    PubMed

    Verma, Rajesh; Arya, Kamal Narayan; Sharma, Pawan; Garg, R K

    2012-01-01

    The role of the brain in post-stroke gait is not understood properly, although the ability to walk becomes impaired in more than 80% of post-stroke patients. Most, however, regain some ability to walk with either limited mobility or inefficient, asymmetrical or unsafe gait. Conventional intervention focuses on support of weak muscles or body part by use of foot orthosis and walking aids. This review provides an overview of available evidence of neuro-kinesiology & neurophysiology of normal and post-stroke gait. The role of the spinal cord has been explored, more in animals than humans. Mammalian locomotion is based on a rhythmic, "pacemaker" activity of the spinal stepping generators. Bipedal human locomotion is different from quadripedal animal locomotion. However, knowledge derived from the spinal cord investigation of animals, is being applied for management of human gait dysfunction. The potential role of the brain is now recognized in the independent activation of muscles during walking. The brain modifies the gait pattern during the complex demands of daily activities. Though the exact role of the motor cortex in control of gait is unclear, available evidence may be applied to gait rehabilitation of post-stroke patients. PMID:22196422

  11. Role of attentional resources on gait performance in Huntington's disease.

    PubMed

    Delval, Arnaud; Krystkowiak, Pierre; Delliaux, Marie; Dujardin, Kathy; Blatt, Jean-Louis; Destée, Alain; Derambure, Philippe; Defebvre, Luc

    2008-04-15

    Patients with Huntington's disease (HD) suffer from cognitive deficits with impaired executive functions, including limited attentional resources. We sought to use a dual-task paradigm to evaluate attentional demands and the ability of patients with HD to concentrate on two tasks simultaneously. We analyzed the interference effects of cognitive and motor tasks on walking in HD and the contribution of clinical symptoms to gait disturbances. Patients and controls were asked to perform either a motor task (carrying a tray with four glasses), a cognitive task (counting backwards), or no task at all while walking at their preferred speed. Kinematic spatial parameters, temporal parameters, and angular parameters related to gait were recorded in 15 patients and 15 controls by means of a videomotion analysis system. Gait instability was assessed using the stride-to-stride variability of the various gait parameters. For patients with HD, performing a concurrent cognitive task resulted in a lower gait speed (compared with free walking), with decreased cadence and stride length. However, this effect was not observed in controls. Performing a motor task did not change any kinematic gait parameters in either HD or control subjects. We found correlations between gait speed in the dual cognitive/walking task on one hand and the motor UHDRS score, cognitive status and executive function on the other. Patients with HD had greater difficulty walking while performing a concurrent cognitive task; the drain on attentional resources deteriorated walking performance. PMID:18175353

  12. Gait variability and basal ganglia disorders: stride-to-stride variations of gait cycle timing in Parkinson's disease and Huntington's disease

    NASA Technical Reports Server (NTRS)

    Hausdorff, J. M.; Cudkowicz, M. E.; Firtion, R.; Wei, J. Y.; Goldberger, A. L.

    1998-01-01

    The basal ganglia are thought to play an important role in regulating motor programs involved in gait and in the fluidity and sequencing of movement. We postulated that the ability to maintain a steady gait, with low stride-to-stride variability of gait cycle timing and its subphases, would be diminished with both Parkinson's disease (PD) and Huntington's disease (HD). To test this hypothesis, we obtained quantitative measures of stride-to-stride variability of gait cycle timing in subjects with PD (n = 15), HD (n = 20), and disease-free controls (n = 16). All measures of gait variability were significantly increased in PD and HD. In subjects with PD and HD, gait variability measures were two and three times that observed in control subjects, respectively. The degree of gait variability correlated with disease severity. In contrast, gait speed was significantly lower in PD, but not in HD, and average gait cycle duration and the time spent in many subphases of the gait cycle were similar in control subjects, HD subjects, and PD subjects. These findings are consistent with a differential control of gait variability, speed, and average gait cycle timing that may have implications for understanding the role of the basal ganglia in locomotor control and for quantitatively assessing gait in clinical settings.

  13. The gait standard deviation, a single measure of kinematic variability.

    PubMed

    Sangeux, Morgan; Passmore, Elyse; Graham, H Kerr; Tirosh, Oren

    2016-05-01

    Measurement of gait kinematic variability provides relevant clinical information in certain conditions affecting the neuromotor control of movement. In this article, we present a measure of overall gait kinematic variability, GaitSD, based on combination of waveforms' standard deviation. The waveform standard deviation is the common numerator in established indices of variability such as Kadaba's coefficient of multiple correlation or Winter's waveform coefficient of variation. Gait data were collected on typically developing children aged 6-17 years. Large number of strides was captured for each child, average 45 (SD: 11) for kinematics and 19 (SD: 5) for kinetics. We used a bootstrap procedure to determine the precision of GaitSD as a function of the number of strides processed. We compared the within-subject, stride-to-stride, variability with the, between-subject, variability of the normative pattern. Finally, we investigated the correlation between age and gait kinematic, kinetic and spatio-temporal variability. In typically developing children, the relative precision of GaitSD was 10% as soon as 6 strides were captured. As a comparison, spatio-temporal parameters required 30 strides to reach the same relative precision. The ratio stride-to-stride divided by normative pattern variability was smaller in kinematic variables (the smallest for pelvic tilt, 28%) than in kinetic and spatio-temporal variables (the largest for normalised stride length, 95%). GaitSD had a strong, negative correlation with age. We show that gait consistency may stabilise only at, or after, skeletal maturity. PMID:27131201

  14. The integrative role of the pedunculopontine nucleus in human gait.

    PubMed

    Lau, Brian; Welter, Marie-Laure; Belaid, Hayat; Fernandez Vidal, Sara; Bardinet, Eric; Grabli, David; Karachi, Carine

    2015-05-01

    The brainstem pedunculopontine nucleus has a likely, although unclear, role in gait control, and is a potential deep brain stimulation target for treating resistant gait disorders. These disorders are a major therapeutic challenge for the ageing population, especially in Parkinson's disease where gait and balance disorders can become resistant to both dopaminergic medication and subthalamic nucleus stimulation. Here, we present electrophysiological evidence that the pedunculopontine and subthalamic nuclei are involved in distinct aspects of gait using a locomotor imagery task in 14 patients with Parkinson's disease undergoing surgery for the implantation of pedunculopontine or subthalamic nuclei deep brain stimulation electrodes. We performed electrophysiological recordings in two phases, once during surgery, and again several days after surgery in a subset of patients. The majority of pedunculopontine nucleus neurons (57%) recorded intrasurgically exhibited changes in activity related to different task components, with 29% modulated during visual stimulation, 41% modulated during voluntary hand movement, and 49% modulated during imaginary gait. Pedunculopontine nucleus local field potentials recorded post-surgically were modulated in the beta and gamma bands during visual and motor events, and we observed alpha and beta band synchronization that was sustained for the duration of imaginary gait and spatially localized within the pedunculopontine nucleus. In contrast, significantly fewer subthalamic nucleus neurons (27%) recorded intrasurgically were modulated during the locomotor imagery, with most increasing or decreasing activity phasically during the hand movement that initiated or terminated imaginary gait. Our data support the hypothesis that the pedunculopontine nucleus influences gait control in manners extending beyond simply driving pattern generation. In contrast, the subthalamic nucleus seems to control movement execution that is not likely to be gait-specific. These data highlight the crucial role of these two nuclei in motor control and shed light on the complex functions of the lateral mesencephalus in humans. PMID:25765327

  15. Observational gait assessment tools in paediatrics--a systematic review.

    PubMed

    Rathinam, Chandrasekar; Bateman, Andrew; Peirson, Janet; Skinner, Jane

    2014-06-01

    Instrumented gait analysis (IGA) is an expensive technique used to objectively detect gait abnormalities in children. Observational gait assessment is considered as a cost effective alternate for IGA in regular clinical practice. This article is aimed at systematically reviewing the available paediatric gait analysis tools and examines their reliability and validity compared to IGA. This review also examines the structure of these tools, their clinical use and limitations. Articles were searched from PubMed, CINHL, AMED, BNI, EMBASE, PEDro and Cochrane library from the earliest record on the database to December 2012. Hand searches were carried out in a few journals. Studies that examined children's gait using a structured assessment tool were included and analysed for their quality, reliability and validity. Pre-established criteria were used to judge the quality of methodology and reliability and validity. Five observational gait tools for children with Cerebral Palsy (CP) and one for children with Downs Syndrome were identified. Nine studies related to children with CP were enrolled for this review. None of the tools have accomplished the level of IGA's consistency. Edinburgh Visual Gait Score (EVGS) was found to have better reliability and validity than the other tools. Very limited studies were available for most of the gait assessment tools therefore their clinical use cannot be judged based on the existing evidence. EVGS was found to have better concurrent validity and reliability and it should be considered to assess CP gait in regular practice. Future work to investigate the use of low cost technology to improve observers' accuracy of EVGS is suggested. PMID:24798609

  16. Gait and menstrual cycle: ovulating women use sexier gaits and walk slowly ahead of men.

    PubMed

    Guéguen, Nicolas

    2012-04-01

    Previous research has demonstrated that women's physical appearance or sexual interest is different across the menstrual cycle. However, the nonverbal behavior of women toward men according to their menstrual cycle has not been previously explored. In this study, the gait of women walking ahead a male confederate was recorded with the help of a spy-camera. The amount of time that women spent walking was the first dependent variable whereas the extent to which the women were perceived to be sexually attractive by two judges was the second dependent variable. Comparisons were performed according to the women's ovulation phase measured with an LH salivary test. Near ovulation, it was found that women walked slower and their gait was subjectively rated as sexier. Such behaviors were interpreted as unconscious desires of women near ovulation to reinforce their attractiveness in order to attract more men and to increase their choice of a partner. PMID:22245227

  17. Clinical signs in functional (psychogenic) gait disorders: a brief survey.

    PubMed

    Sokol, Leonard L; Espay, Alberto J

    2016-01-01

    Clinical signs are critical in ascertaining the functional nature of a gait disorder. Four signs of gait impairment have been documented in the course of examining patients with clinically definite functional (psychogenic) movement disorders: "huffing and puffing" during standing and walking, manipulation-resistance dorsiflexion of the first toe, fixed plantar flexion and inversion, and marked discrepancy between ambulation with and without swivel chair assistance. While large studies are needed to ascertain their prevalence, sensitivity, and specificity, the identification of these signs may help elevate the diagnostic certainty of functional gait disorders. PMID:26877882

  18. ADAPTIVE CONTROL OF CENTER OF MASS (GLOBAL) MOTION AND ITS JOINT (LOCAL) ORIGIN IN GAIT

    PubMed Central

    Yang, Feng; Pai, Yi-Chung

    2014-01-01

    Dynamic gait stability can be quantified by the relationship of the motion state (i.e. the position and velocity) between the body center of mass (COM) and its base of support (BOS). Humans learn how to adaptively control stability by regulating the absolute COM motion state (i.e., its position and velocity) or by controlling the BOS (through stepping) in a predictable manner, or by doing both simultaneously following an external perturbation that disrupts their regular relationship. Post repeated-slip perturbation training, for instance, older adults learned to forward shift their COM position while walking with a reduced step length, hence reduced their likelihood of falls. How and to what extent each individual joint influences such adaptive alterations is mostly unknown. A three-dimensional individualized human kinematic model was established. Based on the human model, sensitivity analysis was used to systematically quantify the influence of each lower limb joint on the COM position relative to the BOS and the step length during gait. It was found that the leading foot had the greatest effect on regulating the COM position relative to the BOS; and both hips bear the most influence on the step length. These findings could guide cost-effective but efficient fall-reduction training paradigm among older population. PMID:24998991

  19. A robust real-time gait event detection using wireless gyroscope and its application on normal and altered gaits.

    PubMed

    Gouwanda, Darwin; Gopalai, Alpha Agape

    2015-02-01

    Gait events detection allows clinicians and biomechanics researchers to determine timing of gait events, to estimate duration of stance phase and swing phase and to segment gait data. It also aids biomedical engineers to improve the design of orthoses and FES (functional electrical stimulation) systems. In recent years, researchers have resorted to using gyroscopes to determine heel-strike (HS) and toe-off (TO) events in gait cycles. However, these methods are subjected to significant delays when implemented in real-time gait monitoring devices, orthoses, and FES systems. Therefore, the work presented in this paper proposes a method that addresses these delays, to ensure real-time gait event detection. The proposed algorithm combines the use of heuristics and zero-crossing method to identify HS and TO. Experiments involving: (1) normal walking; (2) walking with knee brace; and (3) walking with ankle brace for overground walking and treadmill walking were designed to verify and validate the identified HS and TO. The performance of the proposed method was compared against the established gait detection algorithms. It was observed that the proposed method produced detection rate that was comparable to earlier reported methods and recorded reduced time delays, at an average of 100 ms. PMID:25619613

  20. The Effect of Tai Chi Exercise on Gait Initiation and Gait Performance in Persons with Parkinsons Disease

    PubMed Central

    Amano, Shinichi; Nocera, Joe R.; Vallabhajosula, Srikant; Juncos, Jorge L.; Gregor, Robert J.; Waddell, Dwight E.; Wolf, Steven L.; Hass, Chris J.

    2013-01-01

    Gait dysfunction and postural instability are two debilitating symptoms in persons with Parkinsons disease (PD). Tai Chi exercise has recently gained attention as an attractive intervention for persons with PD because of its known potential to reduce falls and improve postural control, walking abilities, and safety at a low cost. The purpose of this report is to investigate the effect of Tai Chi exercise on dynamic postural control during gait initiation and gait performance in persons with idiopathic PD, and to determine whether these benefits could be replicated in two different environments, as complementary projects. In these two separate projects, a total of 45 participants with PD were randomly assigned to either a Tai Chi group or a control group. The Tai Chi groups in both projects completed a 16-week Tai Chi exercise session, while the control groups consisted of either a placebo (i.e., Qi-Gong) or non-exercise group. Tai Chi did not significantly improve Unified Parkinsons Disease Rating Scale Part III score, selected gait initiation parameters or gait performance in either project. Combined results from both projects suggest that 16 weeks of class-based Tai Chi were ineffective in improving either gait initiation, gait performance, or reducing parkinsonian disability in this subset of persons with PD. Thus the use of short-term Tai Chi exercise should require further study before being considered a valuable therapeutic intervention for these domains in PD. PMID:23835431

  1. Gait evaluation of a novel hip constraint orthosis with implication for walking in paraplegia.

    PubMed

    Audu, Musa L; To, Curtis S; Kobetic, Rudi; Triolo, Ronald J

    2010-12-01

    The aim of this study was to determine the effects of a newly developed reciprocal gait orthosis (RGO) with a variable constraint hip mechanism (VCHM) on the kinematics and kinetics of normal gait. The VCHM was compared with the isocentric reciprocating gait orthosis (IRGO) for walking after paraplegia. Both the VCHM and the IRGO were evaluated with able-bodied volunteers with the hip reciprocating mechanisms coupled and uncoupled. The VCHM was further evaluated with context-dependent coupling based on a finite-state control algorithm utilizing information from brace-mounted sensors. Walking performance for each brace condition was also compared to normal walking without an orthosis. Without the hip controller, the VCHM affected the kinematics of the hip joint in a similar manner as the IRGO, regardless of whether the hip reciprocator was coupled or uncoupled. With the controller active, hip kinematics with the VCHM were closer to normal gait than with the IRGO or any other condition tested (Intraclass correlation coefficient, ICC=0.96). The effects of the braces on the knee and ankle angles were not as prominent as their effects on the hip angles. In terms of kinetics, the VCHM with controller active allowed the generation of joint moments that were closer to normal (ICC=0.80) than the IRGO with hips coupled (ICC= 0.68). There was no statistically significant difference between the various conditions tested in terms of step-length and no statistically significant difference in the preferred walking speed between the IRGO and normal walking, whether or not the hips were coupled. However, there was a 25% reduction in walking speed with the VCHM when compared to normal, and the relative magnitudes of the EMG activity of three muscles (tibialis anterior, quadriceps, and hamstrings) were also higher with the VCHM than with either the IRGO or normal gait, likely due to the additional weight of the mechanism. Overall, the VCHM with controller active provided smooth control of the hip joints via context-dependent coupling and allowed for increased hip flexion relative to the IRGO. The results suggest that the VCHM with controlled joint coupling may eventually be a valuable component of a hybrid system combining functional electrical stimulation (FES) with orthotics. PMID:20378478

  2. Concurrent prediction of muscle and tibiofemoral contact forces during treadmill gait.

    PubMed

    Guess, Trent M; Stylianou, Antonis P; Kia, Mohammad

    2014-02-01

    Detailed knowledge of knee kinematics and dynamic loading is essential for improving the design and outcomes of surgical procedures, tissue engineering applications, prosthetics design, and rehabilitation. This study used publicly available data provided by the "Grand Challenge Competition to Predict in-vivo Knee Loads" for the 2013 American Society of Mechanical Engineers Summer Bioengineering Conference (Fregly et al., 2012, "Grand Challenge Competition to Predict in vivo Knee Loads," J. Orthop. Res., 30, pp. 503-513) to develop a full body, musculoskeletal model with subject specific right leg geometries that can concurrently predict muscle forces, ligament forces, and knee and ground contact forces. The model includes representation of foot/floor interactions and predicted tibiofemoral joint loads were compared to measured tibial loads for two different cycles of treadmill gait. The model used anthropometric data (height and weight) to scale the joint center locations and mass properties of a generic model and then used subject bone geometries to more accurately position the hip and ankle. The musculoskeletal model included 44 muscles on the right leg, and subject specific geometries were used to create a 12 degrees-of-freedom anatomical right knee that included both patellofemoral and tibiofemoral articulations. Tibiofemoral motion was constrained by deformable contacts defined between the tibial insert and femoral component geometries and by ligaments. Patellofemoral motion was constrained by contact between the patellar button and femoral component geometries and the patellar tendon. Shoe geometries were added to the feet, and shoe motion was constrained by contact between three shoe segments per foot and the treadmill surface. Six-axis springs constrained motion between the feet and shoe segments. Experimental motion capture data provided input to an inverse kinematics stage, and the final forward dynamics simulations tracked joint angle errors for the left leg and upper body and tracked muscle length errors for the right leg. The one cycle RMS errors between the predicted and measured tibia contact were 178 N and 168 N for the medial and lateral sides for the first gait cycle and 209 N and 228 N for the medial and lateral sides for the faster second gait cycle. One cycle RMS errors between predicted and measured ground reaction forces were 12 N, 13 N, and 65 N in the anterior-posterior, medial-lateral, and vertical directions for the first gait cycle and 43 N, 15 N, and 96 N in the anterior-posterior, medial-lateral, and vertical directions for the second gait cycle. PMID:24389997

  3. Understanding the complexity of human gait dynamics

    NASA Astrophysics Data System (ADS)

    Scafetta, Nicola; Marchi, Damiano; West, Bruce J.

    2009-06-01

    Time series of human gait stride intervals exhibit fractal and multifractal properties under several conditions. Records from subjects walking at normal, slow, and fast pace speed are analyzed to determine changes in the fractal scalings as a function of the stress condition of the system. Records from subjects with different age from children to elderly and patients suffering from neurodegenerative disease are analyzed to determine changes in the fractal scalings as a function of the physical maturation or degeneration of the system. A supercentral pattern generator model is presented to simulate the above two properties that are typically found in dynamical network performance: that is, how a dynamical network responds to stress and to evolution.

  4. On using gait in forensic biometrics.

    PubMed

    Bouchrika, Imed; Goffredo, Michaela; Carter, John; Nixon, Mark

    2011-07-01

    Given the continuing advances in gait biometrics, it appears prudent to investigate the translation of these techniques for forensic use. We address the question as to the confidence that might be given between any two such measurements. We use the locations of ankle, knee, and hip to derive a measure of the match between walking subjects in image sequences. The Instantaneous Posture Match algorithm, using Harr templates, kinematics, and anthropomorphic knowledge is used to determine their location. This is demonstrated using real CCTV recorded at Gatwick International Airport, laboratory images from the multiview CASIA-B data set, and an example of real scene of crime video. To access the measurement confidence, we study the mean intra- and inter-match scores as a function of database size. These measures converge to constant and separate values, indicating that the match measure derived from individual comparisons is considerably smaller than the average match measure from a population. PMID:21554307

  5. Fractal and Multifractal Analysis of Human Gait

    NASA Astrophysics Data System (ADS)

    Muñoz-Diosdado, A.; del Río Correa, J. L.; Angulo-Brown, F.

    2003-09-01

    We carried out a fractal and multifractal analysis of human gait time series of young and old individuals, and adults with three illnesses that affect the march: The Parkinson's and Huntington's diseases and the amyotrophic lateral sclerosis (ALS). We obtained cumulative plots of events, the correlation function, the Hurst exponent and the Higuchi's fractal dimension of these time series and found that these fractal markers could be a factor to characterize the march, since we obtained different values of these quantities for youths and adults and they are different also for healthy and ill persons and the most anomalous values belong to ill persons. In other physiological signals there is complexity lost related with the age and the illness, in the case of the march the opposite occurs. The multifractal analysis could be also a useful tool to understand the dynamics of these and other complex systems.

  6. Contributions to the understanding of gait control.

    PubMed

    Simonsen, Erik Bruun

    2014-04-01

    This thesis is based on ten published articles. The experimental work was carried out at the Faculty of Health Sciences, University of Copenhagen. The aim was to investigate and describe a number of basic mechanical and physiological mechanisms behind human walking. The methodologies used were biomechanical movement analysis and electrophysiology. The walking experiments were carried out in a gait lab, where the subjects were video recorded while they walked across two force platforms, which measured the ground reaction forces. Net joint moments about the hip-, knee- and ankle joint were calculated by combining the movement data and the external reaction forces (inverse dynamics). Muscle activity and sensory input to the spinal cord were measured by electromyography (EMG) and electrical stimulation of peripheral nerves. The results showed that the gait pattern varies to a great degree between individuals. Some people choose to exert the highest forces about the ankle joint while others prefer to use the knee joint. By use of a cluster analysis, fifteen healthy subjects could be divided into two groups. The extensor moment about the knee joint was the main factor for separating the two gait patterns, but the group with the highest extensor moments about the knee joint also walked with more flexed knee joints, higher EMG activity in the quadriceps muscle and higher bone-on-bone forces. This may lead to development of osteoarthritis over the years. Walking on high-heeled shoes reduced the ankle joint moment significantly either because of reduced muscle fiber length and/or increased co-contraction about the joint. On the contrary, the extensor moment about the knee joint was almost doubled in the high-heeled condition compared to bare footed walking at the same velocity. Also the EMG activity increased in the leg muscles. This could be an explanation pertaining to the higher incidence of osteoarthritis in women than in men. Patients with a drop-foot cannot put the foot to the ground with the heel first. Moreover, they have to increase flexion of the hip joint during the swing phase because the foot hangs in a plantar flexed position. It was shown that the ankle joint plantar flexor moment increased in the healthy leg and that the knee joint extensor moment increased significantly in both the affected and the healthy leg. The latter is most likely due to the patients trying to avoid an asymmetrical gait pattern. It is recommended to use an orthosis with drop-foot patients in order to keep the ankle joint dorsiflexed prior to touchdown, otherwise bone-on-bone forces in both knee joints will increase and probably lead to osteoarthritis. The hip joint moment varies less between individuals. However, both during walking and running an unexplained hip joint flexor moment is present during the last half of the stance phase. The moment appears to oppose the speed of progression and it has been suggested that it serves to balance the upper body. This was investigated in a group of healthy subjects who were asked to walk with their upper body in a reclined, inclined and normal position, respectively. It was shown that the hip joint flexor moment was similar in the reclined and the normal position but lower when walking in the inclined position and it can be concluded that the upper body is not balanced by hip joint flexor muscles but rather by accelerations of the pelvis and activity in abdominal and back muscles. These experiments also showed that the trailing leg is brought forward during the swing phase without activity in the flexor muscles about the hip joint. This was verified by the absence of EMG activity in the iliacus muscle measured by intramuscular wire electrodes. Instead the strong ligaments restricting hip joint extension are stretched during the first half of the swing phase thereby storing elastic energy, which is released during the last half of the stance phase and accelerating the leg into the swing phase. This is considered an important energy conserving feature of human walking. The gating of sensory input to the spinal cord during walking and running was investigated by use of the Hoffmann (H) reflex in m. soleus and m. gastrocnemius medialis. This reflex expresses the central component of the stretch reflex, i.e. the transmission from Ia afferents to α-motoneurones in the spinal cord. The soleus H-reflex was shown to be strongly modulated during the gait cycle. In general, it was facilitated in the stance phase and suppressed in the swing phase. However, as it was the case with the biomechanical parameters, inter-individual H-reflex modulations were found and they were highly reproducible between days. One group of subjects had an almost completely suppressed H-reflex during the entire swing phase, while another group showed a gradually increasing reflex excitability during the swing phase. This group also walked with a lower extensor moment about the knee joint and higher plantar flexor moment about the ankle joint and it is speculated that this gait pattern highly relies on reflexes to deal with unexpected perturbations. The subjects with the suppressed reflex during the swing phase also showed a higher EMG activity in the anterior tibial muscle, so it is likely that the suppression of the H-reflex was at least partly due to reciprocal antagonist inhibition. All subjects showed complete suppression of the H-reflex at toeoff. This seems necessary to avoid a stretch reflex being elicited in the soleus muscle as the ankle joint undergoes a fast dorsiflexion just after toeoff. The reflex modulation is clearly an integrated part of the human gait pattern and is absolutely necessary for normal gait function with smoothe movements. Furthermore, it is anticipated that the afferent input from the muscle spindles is used to drive the motor output from the α-motoneurones together with descending activity from the motor cortex. During running the H-reflex increased in both the soleus and the gastrocnemius already before heel strike and before the onset of EMG activity in the same two muscles and with a relatively high activity in the anterior tibial muscle, but this was most pronounced in the soleus. The H-reflex was always higher in the soleus also when expressed as percentage of the maximal M-wave. This is due to the difference in muscle fiber type distribution between the two muscles. The H-reflex increased from walking to running in both muscles and further with increasing running speed. Unexpectedly, there were no signs of the faster gastrocnemius becoming more important at higher running speed. During walking it is not possible to observe a stretch reflex in the form of a synchronized activation of a large number of muscle fibers as this would disturb the movement pattern. It is rather likely that the input from Ia afferents directly contributes to activate the α-motoneurones. However, during running the stance phase is much shorter, which enables the possibility of a stretch reflex to contribute to a strong contraction during push-off. EMG peaks in the soleus with an appropriate latency were observed in the soleus during running. This was not the case with the gastrocnemius and the explanation is most likely that the gastrocnemius is biarticular and not stretched to any great extent during running. PMID:24814597

  7. Mechanical spin bearings

    NASA Technical Reports Server (NTRS)

    Vranish, John M. (Inventor)

    1998-01-01

    A spin bearing assembly including, a pair of mutually opposing complementary bearing support members having mutually spaced apart bearing support surfaces which may be, for example, bearing races and a set of spin bearings located therebetween. Each spin bearing includes a pair of end faces, a central rotational axis passing through the end faces, a waist region substantially mid-way between the end faces and having a first thickness dimension, and discrete side surface regions located between the waist region and the end faces and having a second thickness dimension different from the first thickness dimension of the waist region and wherein the side surface regions further have respective curvilinear contact surfaces adapted to provide a plurality of bearing contact points on the bearing support members.

  8. Experiments with needle bearings

    NASA Technical Reports Server (NTRS)

    Ferretti, Pericle

    1933-01-01

    Experiments and results are presented in testing needle bearings, especially in comparison with roller bearings. Reduction in coefficient of friction is discussed as well as experimental methods and recording devices.

  9. Detection of Freezing of Gait in Parkinson Disease: Preliminary Results

    PubMed Central

    Coste, Christine Azevedo; Sijobert, Benoît; Pissard-Gibollet, Roger; Pasquier, Maud; Espiau, Bernard; Geny, Christian

    2014-01-01

    Freezing of gait (FOG) is a common symptom in Parkinsonism, which affects the gait pattern and is associated to a fall risk. Automatized FOG episode detection would allow systematic assessment of patient state and objective evaluation of the clinical effects of treatments. Techniques have been proposed in the literature to identify FOG episodes based on the frequency properties of inertial sensor signals. Our objective here is to adapt and extend these FOG detectors in order to include other associated gait pattern changes, like festination. The proposed approach is based on a single wireless inertial sensor placed on the patient's lower limbs. The preliminary experimental results show that existing frequency-based freezing detectors are not sufficient to detect all FOG and festination episodes and that the observation of some gait parameters such as stride length and cadence are valuable inputs to anticipate the occurrence of upcoming FOG events. PMID:24740014

  10. Visualising gait symmetry/asymmetry from acceleration data.

    PubMed

    Yoneyama, Mitsuru

    2015-07-01

    Accelerometry-based quantification of gait symmetry/asymmetry is a promising approach for objectively evaluating gait dysfunctions. An important step in the application of this method in clinical settings is to develop reliable gait asymmetry measures and tools for visualising them to create easy-to-understand presentations for both clinicians and patients. This paper describes a new self-adaptive algorithm for estimating motion trajectory from acceleration data and visualising the degree of its asymmetry in 3D space. Two new parameters are introduced to capture asymmetric walking patterns based on the assessment of 3D autocorrelation and biphasicity of the motion trajectory. The performance of our algorithm is confirmed by analysing gait data collected from 245 healthy subjects. The proposed method may be clinically useful in tracking the process of recovering from pathology or injury after rehabilitation. PMID:24266651

  11. Correlation of residual limb length and gait parameters in amputees.

    PubMed

    Baum, Brian S; Schnall, Barri L; Tis, John E; Lipton, Jill S

    2008-07-01

    There is a lack of objective data on acceptable transection levels for transfemoral amputation. We retrospectively correlated the residual limb length of 13 young, athletic transfemoral and knee disarticulation amputees with temporal-spatial, kinematic, and kinetic outcomes after gait analysis. It was hypothesised that shorter residual limb lengths would correlate with greater gait deviations. Patients' residual femoral lengths ranged from 57% to 100% of their intact femoral length. With the exception of one patient, pelvic tilt excursion was inversely related to residual limb length. Limb length did not significantly correlate with any other temporal-spatial, kinematic, or kinetic parameter investigated. Consequently, these results suggest that if the femur is at least 57% of the length of the contralateral femur, length does not dramatically alter gait. This implies that surgeons may have more flexibility to amputate at a higher level to preserve soft tissue quality and improve prosthetic fitting without sacrificing gait function. PMID:18541239

  12. Interpolation function for approximating knee joint behavior in human gait

    NASA Astrophysics Data System (ADS)

    Toth-Taşcǎu, Mirela; Pater, Flavius; Stoia, Dan Ioan

    2013-10-01

    Starting from the importance of analyzing the kinematic data of the lower limb in gait movement, especially the angular variation of the knee joint, the paper propose an approximation function that can be used for processing the correlation among a multitude of knee cycles. The approximation of the raw knee data was done by Lagrange polynomial interpolation on a signal acquired using Zebris Gait Analysis System. The signal used in approximation belongs to a typical subject extracted from a lot of ten investigated subjects, but the function domain of definition belongs to the entire group. The study of the knee joint kinematics plays an important role in understanding the kinematics of the gait, this articulation having the largest range of motion in whole joints, in gait. The study does not propose to find an approximation function for the adduction-abduction movement of the knee, this being considered a residual movement comparing to the flexion-extension.

  13. Gait recognition under carrying condition: a static dynamic fusion method

    NASA Astrophysics Data System (ADS)

    Yu, Guan; Li, Chang-Tsun; Hu, Yongjian

    2012-06-01

    When an individual carries an object, such as a briefcase, conventional gait recognition algorithms based on average silhouette/Gait Energy Image (GEI) do not always perform well as the object carried may have the potential of being mistakenly regarded as a part of the human body. To solve such a problem, in this paper, instead of directly applying GEI to represent the gait information, we propose a novel dynamic feature template for classification. Based on this extracted dynamic information and some static feature templates (i.e., head part and trunk part), we cast gait recognition on the large USF (University of South Florida) database by adopting a static/dynamic fusion strategy. For the experiments involving carrying condition covariate, significant improvements are achieved when compared with other classic algorithms.

  14. A wireless gait analysis system by digital textile sensors.

    PubMed

    Yang, Chang-Ming; Chou, Chun-Mei; Hu, Jwu-Sheng; Hung, Shu-Hui; Yang, Chang-Hwa; Wu, Chih-Chung; Hsu, Ming-Yang; Yang, Tsi-Lin

    2009-01-01

    This paper studies the feasibility of spatio-temporal gait analysis based upon digital textile sensors. Digitized legs and feet patterns of healthy subjects and their relations with spatio-temporal gait parameters were analyzed. In the first experiment, spatio-temporal gait parameters were determined during over ground walking. In the second experiment, predicted running, backward walking, walking up stairs and walking down stairs parameters were determined. From the results of the experiments, it is concluded that, for healthy subjects, the duration of subsequent stride cycles and left/right steps, the estimations of step length, cadence, walking speed, central of pressure and central of mass trajectory, can be obtained by analyzing the digital signals from the textile sensors on pants and socks. These parameters are easily displayed in several different graphs allowing the user to view the parameters during gait. Finally, the digital data are easily to analyze the feature of activity recognition. PMID:19965098

  15. Low Power Shoe Integrated Intelligent Wireless Gait Measurement System

    NASA Astrophysics Data System (ADS)

    Wahab, Y.; Mazalan, M.; Bakar, N. A.; Anuar, A. F.; Zainol, M. Z.; Hamzah, F.

    2014-04-01

    Gait analysis measurement is a method to assess and identify gait events and the measurements of dynamic, motion and pressure parameters involving the lowest part of the body. This significant analysis is widely used in sports, rehabilitation as well as other health diagnostic towards improving the quality of life. This paper presents a new system empowered by Inertia Measurement Unit (IMU), ultrasonic sensors, piezoceramic sensors array, XBee wireless modules and Arduino processing unit. This research focuses on the design and development of a low power ultra-portable shoe integrated wireless intelligent gait measurement using MEMS and recent microelectronic devices for foot clearance, orientation, error correction, gait events and pressure measurement system. It is developed to be cheap, low power, wireless, real time and suitable for real life in-door and out-door environment.

  16. Effect of gait on formation of thermal environment inside footwear.

    PubMed

    Shimazaki, Yasuhiro; Murata, Masaaki

    2015-07-01

    In this study, the relationship between the gait condition and foot temperature distributions inside footwear was investigated using subject experiments. Mechanical, physical, and physiological variables such as the foot contact force, landing speed, and metabolic heat generation were also measured. Gait motion measurements showed that a large contact force was concentrated in the small area of the heel at the initial contact and later at the forefoot. A faster gait produced a larger contact force, higher landing velocity, higher skin temperature, and larger metabolism during gait. The temperature at the bottom of the foot increased, and the temperature on the upper side decreased. The metabolic heat generation had a basic impact on the temperature profile, and skin temperatures tended to increase gradually. In addition, high-temperature-elevation regions such as the big toe and heel coincided with regions with high-contact loads, which suggested a relationship between the temperature elevation and contact load. PMID:25766423

  17. Axial Halbach Magnetic Bearings

    NASA Technical Reports Server (NTRS)

    Eichenberg, Dennis J.; Gallo, Christopher A.; Thompson, William K.

    2008-01-01

    Axial Halbach magnetic bearings have been investigated as part of an effort to develop increasingly reliable noncontact bearings for future high-speed rotary machines that may be used in such applications as aircraft, industrial, and land-vehicle power systems and in some medical and scientific instrumentation systems. Axial Halbach magnetic bearings are passive in the sense that unlike most other magnetic bearings that have been developed in recent years, they effect stable magnetic levitation without need for complex active control.

  18. Gait Using Pneumatic Brace for End-Stage Knee Osteoarthritis.

    PubMed

    Kapadia, Bhaveen H; Cherian, Jeffrey Jai; Starr, Roland; Chughtai, Morad; Mont, Michael A; Harwin, Steven F; Bhave, Anil

    2016-04-01

    More than 20 million individuals in the United States are affected by knee osteoarthritis (OA), which can lead to altered biomechanics and excessive joint loading. The use of an unloader pneumatic brace with extension assist has been proposed as a nonoperative treatment modality that may improve gait mechanics and correct knee malalignment. We assessed the following parameters in patients who have knee OA treated with and without a brace: (1) changes in temporospatial parameters in gait; (2) knee range of motion, knee extension at heel strike, and foot placement; (3) knee joint moments and impulse; and (4) changes in dynamic stiffness and rate of change of knee flexion during midstance to terminal stance. This 2:1 prospective, randomized, single-blinded trial evaluated 36 patients (24 brace and 12 matching). OA knee patients were randomized to receive either a pneumatic unloader brace or a standard nonoperative treatment regimen as the matching cohort for a 3-month period. They underwent evaluation of gait parameters using a three-dimensional gait analysis system at their initial appointment and at 3 months follow-up. All the testing, pre- and postbracing were performed without wearing the brace to examine for retained effects. Treatment with the brace led to significant improvements versus standard treatment in various gait parameters. Patients in the brace group had improvements in walking speed, knee extension at heel strike, total range of motion, knee joint forces, and rate of knee flexion from midstance to terminal stance when compared with the matching cohort. Knee OA patients who used a pneumatic unloader brace for 3 months for at least 3 hours per day had significant improvements various gait parameters when compared with a standard nonoperative therapy cohort. Braced patients demonstrated gait-modifying affects when not wearing the brace. These results are encouraging and suggest that this device represents a promising treatment modality for knee OA that may improve gait, knee pain, and strength in knee OA patients. PMID:26963073

  19. [Gait disorders in Parkinson's disease: and pathophysiological approaches].

    PubMed

    Moreau, C; Cantiniaux, S; Delval, A; Defebvre, L; Azulay, J-P

    2010-02-01

    Gait disorders and axial symptoms are the main therapeutic challenges in advanced Parkinson's disease (PD). Gait disorders in PD are characterized by spatial and temporal dysfunction. Gait hypokinesia is the first to appear and is responsible for the decrease in velocity. A good sensitivity to the levodopa is well established. Morris et al. [Morris ME, Iansek R, Matyas TA, Summers JJ. Ability to modulate walking cadence remains intact in Parkinson's disease. J Neurol Neurosurg Psychiatry 1994a;57(12):1532-4; Morris ME, Iansek R, Matyas TA, Summers JJ. The pathogenesis of gait hypokinesia in Parkinson's disease. Brain 1994b;117(Pt. 5):1169-81; Morris ME, Iansek R, Matyas TA, Summers JJ. Stride length regulation in Parkinson's disease. Brain 1996;119:551-68] demonstrated that the ability to modulate walking cadence remains intact in PD, and could correspond to a compensatory mechanism. More advanced disease stages of the disease are characterized by abnormal temporal parameters (such as stride length variability, stride time variability and cadence elevation) which are unresponsive to levodopa therapy and may be correlated with the occurrence of falls and freezing of gait (FOG). Lastly, postural instability also results in falls and is poorly responsive to levodopa. A link between gait impairment and frontal disorders has recently been suggested. After a few years of evolution, paradoxical episodic phenomena are described: festination ("hastening gait" with rapid small, short steps) and FOG (involuntary and sudden cessation of gait). Both symptoms are often incapacitating for PD patients, because of their resultant loss of independence and their poor response to levodopa therapy. Kinematical studies of FOG revealed a decrease in velocity, stride length and an exponential increase in cadence, prior to a FOG episode. New approaches (functional MRI, wavelets...) should offer new perspectives concerning these disabling symptoms. PMID:19616816

  20. Tracking Polar Bears

    Movements of 9 satellite-collared adult female polar bears were tracked in February, 2010 by satellite telemetry. Bears were collared in 2007, 2008, and 2009 on the spring-time sea ice of the southern Beaufort Sea or on the autumn pack ice in 2009. Polar bear satellite telemetry data are shown with ...

  1. 1-Way Bearing

    NASA Technical Reports Server (NTRS)

    Vranish, John M. (Inventor)

    2003-01-01

    A one-way bearing is provided having sprags and rolling bearings both disposed between an inner and an outer race. The sprags may comprise three-dimensional sprags for preventing rotation in a non-preferential direction. The roll- ing bearings may comprise thrust rollers for transmitting axial, tilt, and radial loads between the inner and outer races.

  2. Supertough Stainless Bearing Steel

    NASA Technical Reports Server (NTRS)

    Olson, Gregory B.

    1995-01-01

    Composition and processing of supertough stainless bearing steel designed with help of computer-aided thermodynamic modeling. Fracture toughness and hardness of steel exceeds those of other bearing steels like 440C stainless bearing steel. Developed for service in fuel and oxidizer turbopumps on Space Shuttle main engine. Because of strength and toughness, also proves useful in other applications like gears and surgical knives.

  3. Hysteresis in the metachronal-tripod gait transition of insects: A modeling study

    NASA Astrophysics Data System (ADS)

    Fujiki, Soichiro; Aoi, Shinya; Funato, Tetsuro; Tomita, Nozomi; Senda, Kei; Tsuchiya, Kazuo

    2013-07-01

    Locomotion in biological systems involves various gaits, and hysteresis appears when the gaits change in accordance with the locomotion speed. That is, the gaits vary at different locomotion speeds depending on the direction of speed change. Although hysteresis is a typical characteristic of nonlinear dynamic systems, the underlying mechanism for the hysteresis in gait transitions remains largely unclear. In this study, we construct a neuromechanical model of an insect and investigate the dynamic characteristics of its gait and gait transition. The simulation results show that our insect model produces metachronal and tripod gaits depending on the locomotion speed through dynamic interactions among the body mechanical system, the nervous system, and the environment in a self-organized manner. They also show that it undergoes the metachronal-tripod gait transition with hysteresis by changing the locomotion speed. We examined the hysteresis mechanism in the metachronal-tripod gait transition of insects from a dynamic viewpoint.

  4. Wire Weight

    Wire weight is lowered to water surface to measure stage at a site. Levels are made to the wire weights elevation from known benchmarks to ensure correct readings. This wire weight is located along the Missouri River in Bismarck, ND....

  5. Gait Planning and Stability Control of a Quadruped Robot

    PubMed Central

    Li, Junmin; Wang, Jinge; Yang, Simon X.; Zhou, Kedong; Tang, Huijuan

    2016-01-01

    In order to realize smooth gait planning and stability control of a quadruped robot, a new controller algorithm based on CPG-ZMP (central pattern generator-zero moment point) is put forward in this paper. To generate smooth gait and shorten the adjusting time of the model oscillation system, a new CPG model controller and its gait switching strategy based on Wilson-Cowan model are presented in the paper. The control signals of knee-hip joints are obtained by the improved multi-DOF reduced order control theory. To realize stability control, the adaptive speed adjustment and gait switch are completed by the real-time computing of ZMP. Experiment results show that the quadruped robot's gaits are efficiently generated and the gait switch is smooth in the CPG control algorithm. Meanwhile, the stability of robot's movement is improved greatly with the CPG-ZMP algorithm. The algorithm in this paper has good practicability, which lays a foundation for the production of the robot prototype. PMID:27143959

  6. A reinforcement learning approach to gait training improves retention

    PubMed Central

    Hasson, Christopher J.; Manczurowsky, Julia; Yen, Sheng-Che

    2015-01-01

    Many gait training programs are based on supervised learning principles: an individual is guided towards a desired gait pattern with directional error feedback. While this results in rapid adaptation, improvements quickly disappear. This study tested the hypothesis that a reinforcement learning approach improves retention and transfer of a new gait pattern. The results of a pilot study and larger experiment are presented. Healthy subjects were randomly assigned to either a supervised group, who received explicit instructions and directional error feedback while they learned a new gait pattern on a treadmill, or a reinforcement group, who was only shown whether they were close to or far from the desired gait. Subjects practiced for 10 min, followed by immediate and overnight retention and over-ground transfer tests. The pilot study showed that subjects could learn a new gait pattern under a reinforcement learning paradigm. The larger experiment, which had twice as many subjects (16 in each group) showed that the reinforcement group had better overnight retention than the supervised group (a 32% vs. 120% error increase, respectively), but there were no differences for over-ground transfer. These results suggest that encouraging participants to find rewarding actions through self-guided exploration is beneficial for retention. PMID:26379524

  7. User Identification Using Gait Patterns on UbiFloorII

    PubMed Central

    Yun, Jaeseok

    2011-01-01

    This paper presents a system of identifying individuals by their gait patterns. We take into account various distinguishable features that can be extracted from a user’s gait and then divide them into two classes: walking pattern and stepping pattern. The conditions we assume are that our target environments are domestic areas, the number of users is smaller than 10, and all users ambulate with bare feet considering the everyday lifestyle of the Korean home. Under these conditions, we have developed a system that identifies individuals’ gait patterns using our biometric sensor, UbiFloorII. We have created UbiFloorII to collect walking samples and created software modules to extract the user’s gait pattern. To identify the users based on the gait patterns extracted from walking samples over UbiFloorII, we have deployed multilayer perceptron network, a feedforward artificial neural network model. The results show that both walking pattern and stepping pattern extracted from users’ gait over the UbiFloorII are distinguishable enough to identify the users and that fusing two classifiers at the matching score level improves the recognition accuracy. Therefore, our proposed system may provide unobtrusive and automatic user identification methods in ubiquitous computing environments, particularly in domestic areas. PMID:22163758

  8. Automatic identification of gait events using an instrumented sock

    PubMed Central

    2011-01-01

    Background Textile-based transducers are an emerging technology in which piezo-resistive properties of materials are used to measure an applied strain. By incorporating these sensors into a sock, this technology offers the potential to detect critical events during the stance phase of the gait cycle. This could prove useful in several applications, such as functional electrical stimulation (FES) systems to assist gait. Methods We investigated the output of a knitted resistive strain sensor during walking and sought to determine the degree of similarity between the sensor output and the ankle angle in the sagittal plane. In addition, we investigated whether it would be possible to predict three key gait events, heel strike, heel lift and toe off, with a relatively straight-forward algorithm. This worked by predicting gait events to occur at fixed time offsets from specific peaks in the sensor signal. Results Our results showed that, for all subjects, the sensor output exhibited the same general characteristics as the ankle joint angle. However, there were large between-subjects differences in the degree of similarity between the two curves. Despite this variability, it was possible to accurately predict gait events using a simple algorithm. This algorithm displayed high levels of trial-to-trial repeatability. Conclusions This study demonstrates the potential of using textile-based transducers in future devices that provide active gait assistance. PMID:21619570

  9. Temporal and spatial organization of gait-related electrocortical potentials.

    PubMed

    Knaepen, Kristel; Mierau, Andreas; Tellez, Helio Fernandez; Lefeber, Dirk; Meeusen, Romain

    2015-07-10

    To advance gait rehabilitation research it is of great importance to understand the supraspinal control of walking. In this study, the temporal and spatial characteristics of averaged electrocortical activity during treadmill walking in healthy subjects was assessed. Electroencephalography data were recorded from 32 scalp locations, averaged across trials, and related to phases of the gait cycle based on the detection of left heel strike. A characteristic temporal pattern of positive and negative potentials, similar to movement-related cortical potentials, and related to the gait cycle was observed over the cortical leg representation area. Source localization analysis revealed that mainly the primary somatosensory, somatosensory association, primary motor and cingulate cortex were activated during walking. The negative peaks of the gait-related cortical potential were associated with activity predominantly in the cingulate and prefrontal cortex, while the primary motor, primary somatosensory and somatosensory association cortex were mainly active during the positive peaks. This study identified gait-related cortical potentials during walking. The results indicate a widely distributed cortical network involved in gait control. PMID:26003448

  10. A Multiple Regression Approach to Normalization of Spatiotemporal Gait Features.

    PubMed

    Wahid, Ferdous; Begg, Rezaul; Lythgo, Noel; Hass, Chris J; Halgamuge, Saman; Ackland, David C

    2016-04-01

    Normalization of gait data is performed to reduce the effects of intersubject variations due to physical characteristics. This study reports a multiple regression normalization approach for spatiotemporal gait data that takes into account intersubject variations in self-selected walking speed and physical properties including age, height, body mass, and sex. Spatiotemporal gait data including stride length, cadence, stance time, double support time, and stride time were obtained from healthy subjects including 782 children, 71 adults, 29 elderly subjects, and 28 elderly Parkinson's disease (PD) patients. Data were normalized using standard dimensionless equations, a detrending method, and a multiple regression approach. After normalization using dimensionless equations and the detrending method, weak to moderate correlations between walking speed, physical properties, and spatiotemporal gait features were observed (0.01 < |r| < 0.88), whereas normalization using the multiple regression method reduced these correlations to weak values (|r| <0.29). Data normalization using dimensionless equations and detrending resulted in significant differences in stride length and double support time of PD patients; however the multiple regression approach revealed significant differences in these features as well as in cadence, stance time, and stride time. The proposed multiple regression normalization may be useful in machine learning, gait classification, and clinical evaluation of pathological gait patterns. PMID:26426798

  11. FreeWalker: a smart insole for longitudinal gait analysis.

    PubMed

    Wang, Baitong; Rajput, Kuldeep Singh; Tam, Wing-Kin; Tung, Anthony K H; Yang, Zhi

    2015-08-01

    Gait analysis is an important diagnostic measure to investigate the pattern of walking. Traditional gait analysis is generally carried out in a gait lab, with equipped force and body tracking sensors, which needs a trained medical professional to interpret the results. This procedure is tedious, expensive, and unreliable and makes it difficult to track the progress across multiple visits. In this paper, we present a smart insole called FreeWalker, which provides quantitative gait analysis outside the confinement of traditional lab, at low- cost. The insole consists of eight pressure sensors and two motion tracking sensors, i.e. 3-axis accelerometer and 3-axis gyroscope. This enables measurement of under-foot pressure distribution and motion sequences in real-time. The insole is enabled with onboard SD card as well as wireless data transmission, which help in continuous gait-cycle analysis. The data is then sent to a gateway, for analysis and interpretation of data, using a user interface where gait features are graphically displayed. We also present validation result of a subject's left foot, who was asked to perform a specific task. Experiment results show that we could achieve a data-sampling rate of over 1 KHz, transmitting data up to a distance of 20 meter and maintain a battery life of around 24 hours. Taking advantage of these features, FreeWalker can be used in various applications, like medical diagnosis, rehabilitation, sports and entertainment. PMID:26737102

  12. Gait Deviations in Children with Autism Spectrum Disorders: A Review

    PubMed Central

    Kindregan, Deirdre; Gallagher, Louise; Gormley, John

    2015-01-01

    In recent years, it has become clear that children with autism spectrum disorders (ASDs) have difficulty with gross motor function and coordination, factors which influence gait. Knowledge of gait abnormalities may be useful for assessment and treatment planning. This paper reviews the literature assessing gait deviations in children with ASD. Five online databases were searched using keywords “gait” and “autism,” and 11 studies were found which examined gait in childhood ASD. Children with ASD tend to augment their walking stability with a reduced stride length, increased step width and therefore wider base of support, and increased time in the stance phase. Children with ASD have reduced range of motion at the ankle and knee during gait, with increased hip flexion. Decreased peak hip flexor and ankle plantar flexor moments in children with ASD may imply weakness around these joints, which is further exhibited by a reduction in ground reaction forces at toe-off in children with ASD. Children with ASD have altered gait patterns to healthy controls, widened base of support, and reduced range of motion. Several studies refer to cerebellar and basal ganglia involvement as the patterns described suggest alterations in those areas of the brain. Further research should compare children with ASD to other clinical groups to improve assessment and treatment planning. PMID:25922766

  13. Validity of the Kinect for Gait Assessment: A Focused Review.

    PubMed

    Springer, Shmuel; Yogev Seligmann, Galit

    2016-01-01

    Gait analysis may enhance clinical practice. However, its use is limited due to the need for expensive equipment which is not always available in clinical settings. Recent evidence suggests that Microsoft Kinect may provide a low cost gait analysis method. The purpose of this report is to critically evaluate the literature describing the concurrent validity of using the Kinect as a gait analysis instrument. An online search of PubMed, CINAHL, and ProQuest databases was performed. Included were studies in which walking was assessed with the Kinect and another gold standard device, and consisted of at least one numerical finding of spatiotemporal or kinematic measures. Our search identified 366 papers, from which 12 relevant studies were retrieved. The results demonstrate that the Kinect is valid only for some spatiotemporal gait parameters. Although the kinematic parameters measured by the Kinect followed the trend of the joint trajectories, they showed poor validity and large errors. In conclusion, the Kinect may have the potential to be used as a tool for measuring spatiotemporal aspects of gait, yet standardized methods should be established, and future examinations with both healthy subjects and clinical participants are required in order to integrate the Kinect as a clinical gait analysis tool. PMID:26861323

  14. Cerebral correlates of motor imagery of normal and precision gait.

    PubMed

    Bakker, M; De Lange, F P; Helmich, R C; Scheeringa, R; Bloem, B R; Toni, I

    2008-07-01

    We have examined the cerebral structures involved in motor imagery of normal and precision gait (i.e., gait requiring precise foot placement and increased postural control). We recorded cerebral activity with functional magnetic resonance imaging while subjects imagined walking along paths of two different widths (broad, narrow) that required either normal gait, or exact foot placement and increased postural control. We used a matched visual imagery (VI) task to assess the motor specificity of the effects, and monitored task performance by recording imagery times, eye movements, and electromyography during scanning. In addition, we assessed the effector specificity of MI of gait by comparing our results with those of a previous study on MI of hand movements. We found that imagery times were longer for the narrow path during MI, but not during VI, suggesting that MI was sensitive to the constraints imposed by a narrow walking path. Moreover, MI of precision gait resulted in increased cerebral activity and effective connectivity within a network involving the superior parietal lobules, the dorsal precentral gyri, and the right middle occipital gyrus. Finally, the cerebral responses to MI of gait were contiguous to but spatially distinct from regions involved in MI of hand movements. These results emphasize the role of cortical structures outside primary motor regions in imagining locomotion movements when accurate foot positioning and increased postural control is required. PMID:18455930

  15. Validity of the Kinect for Gait Assessment: A Focused Review

    PubMed Central

    Springer, Shmuel; Yogev Seligmann, Galit

    2016-01-01

    Gait analysis may enhance clinical practice. However, its use is limited due to the need for expensive equipment which is not always available in clinical settings. Recent evidence suggests that Microsoft Kinect may provide a low cost gait analysis method. The purpose of this report is to critically evaluate the literature describing the concurrent validity of using the Kinect as a gait analysis instrument. An online search of PubMed, CINAHL, and ProQuest databases was performed. Included were studies in which walking was assessed with the Kinect and another gold standard device, and consisted of at least one numerical finding of spatiotemporal or kinematic measures. Our search identified 366 papers, from which 12 relevant studies were retrieved. The results demonstrate that the Kinect is valid only for some spatiotemporal gait parameters. Although the kinematic parameters measured by the Kinect followed the trend of the joint trajectories, they showed poor validity and large errors. In conclusion, the Kinect may have the potential to be used as a tool for measuring spatiotemporal aspects of gait, yet standardized methods should be established, and future examinations with both healthy subjects and clinical participants are required in order to integrate the Kinect as a clinical gait analysis tool. PMID:26861323

  16. Adaptive changes in spatiotemporal gait characteristics in women during pregnancy.

    PubMed

    Błaszczyk, Janusz W; Opala-Berdzik, Agnieszka; Plewa, Michał

    2016-01-01

    Spatiotemporal gait cycle characteristics were assessed at early (P1), and late (P2) pregnancy, as well as at 2 months (PP1) and 6 months (PP2) postpartum. A substantial decrease in walking speed was observed throughout the pregnancy, with the slowest speed (1±0.2m/s) being during the third trimester. Walking at slower velocity resulted in complex adaptive adjustments to their spatiotemporal gait pattern, including a shorter step length and an increased duration of both their stance and double-support phases. Duration of the swing phase remained the least susceptible to changes. Habitual walking velocity (1.13±0.2m/s) and the optimal gait pattern were fully recovered 6 months after childbirth. Documented here adaptive changes in the preferred gait pattern seem to result mainly from the altered body anthropometry leading to temporary balance impairments. All the observed changes within stride cycle aimed to improve gait safety by focusing on its dynamic stability. The pregnant women preferred to walk at a slower velocity which allowed them to spend more time in double-support compared with their habitual pattern. Such changes provided pregnant women with a safer and more tentative ambulation that reduced the single-support period and, hence, the possibility of instability. As pregnancy progressed a significant increase in stance width and a decrease in step length was observed. Both factors allow also for gait stability improvement. PMID:26480840

  17. Changes in In Vivo Knee Contact Forces through Gait Modification

    PubMed Central

    Kinney, Allison L.; Besier, Thor F.; Silder, Amy; Delp, Scott L.; D’Lima, Darryl D.; Fregly, Benjamin J.

    2012-01-01

    Knee osteoarthritis commonly occurs in the medial compartment of the knee and has been linked to overloading of the medial articular cartilage. Gait modification represents a non-invasive treatment strategy for reducing medial compartment knee force. The purpose of this study was to evaluate the effectiveness of a variety of gait modifications that were expected to alter medial contact force. A single subject implanted with a force-measuring knee replacement walked using nine modified gait patterns, four of which involved different hiking pole configurations. Medial and lateral contact force at 25%, 50%, and 75% of stance phase, and the average value over all of stance phase (0-100%), were determined for each gait pattern. Changes in medial and lateral contact force values relative to the subject’s normal gait pattern were determined by a Kruskal-Wallis test. Apart from early stance (25% of stance), medial contact force was most effectively reduced by walking with long hiking poles and wide pole placement, which significantly reduced medial and lateral contact force during stance phase by up to 34% (at 75% of stance) and 26% (at 50% of stance), respectively. Although this study is based on data from a single subject, the results provide important insight into changes in medial and lateral contact forces through gait modification. The results of this study suggest that an optimal configuration of bilateral hiking poles may significantly reduce both medial and lateral compartment knee forces in individuals with medial knee osteoarthritis. PMID:23027590

  18. Air Bearing Lift Pad (ABLP)

    NASA Technical Reports Server (NTRS)

    Dane, Dan H.; Blaise, Herman T.

    1968-01-01

    Typical air bearings float on air films of only a few thousandths of an inch and so will only operate above very smooth, even surfaces. For the mechanical simulation of space, the small drag of the bladder type air pads is much more than can be coped with, and the practicality of large floor areas being machined for precision air bearings is nonexistent. To enable operation above surfaces that undulate slightly or feature cracks and discontinuities, an ABLP has been developed. It consists of a rigid pad beneath which an inflatable bladder is mounted. The bladder is inflated with air which then escapes through passages into a cavity in the center of the bladder to produce the lifting energy. As the air escapes about the perimeter of the bladder, a certain degree of balance and equilibrium is imparted to the pad as it is able to move a limited weight across slightly uneven surfaces.

  19. Influence of unilateral weight on bilateral cyclograms

    NASA Astrophysics Data System (ADS)

    Pellicer Costa, Juan José; Dusza, Jacek J.

    2014-11-01

    The paper presents the results of gait parameters as a function of unilateral weight. The object of the research was a woman walking on a stationary surface and carrying in his hand weights from 0 to 15 kg. Her movement was recorded by 6 cameras recording the location of 34 markers placed at appropriate points in the body. 3D reconstruction was performed for each of the reflecting markers. Tested signals were changes in the value the joint angles of ankle, knee and hip. On the basis of about 6 cycles of movement of each load, a model for the average gait cycle was developed. The result of the experiments are graphs of changes the joint angles as a function of time, bilateral cyclograms, synchronized bilateral cyclograms and regression lines. The conclusion of the study is to determine how one-sided load affects gait asymmetry. Simple and easy to interpret method of presentation of results were also shown. Studies were conducted using VICON system.

  20. Gait analysis and the cumulative gait index (CGI): Translational tools to assess impairments exhibited by rats with olivocerebellar ataxia.

    PubMed

    Lambert, C S; Philpot, R M; Engberg, M E; Johns, B E; Kim, S H; Wecker, L

    2014-11-01

    Deviations from 'normal' locomotion exhibited by humans and laboratory animals may be determined using automated systems that capture both temporal and spatial gait parameters. Although many measures generated by these systems are unrelated and independent, some may be related and dependent, representing redundant assessments of function. To investigate this possibility, a treadmill-based system was used to capture gait parameters from normal and ataxic rats, and a multivariate analysis was conducted to determine deviations from normal. Rats were trained on the treadmill at two speeds, and gait parameters were generated prior to and following lesions of the olivocerebellar pathway. Control (non-lesioned) animals exhibited stable hindlimb gait parameters across assessments at each speed. Lesioned animals exhibited alterations in multiple hindlimb gait parameters, characterized by significant increases in stride frequency, braking duration, stance width, step angle, and paw angle and decreases in stride, stance, swing and propulsion durations, stride length and paw area. A principal component analysis of initial hindlimb measures indicated three uncorrelated factors mediating performance, termed Rhythmicity, Thrust and Contact. Deviation in the performance of each animal from the group mean was determined for each factor and values summed to yield the cumulative gait index (CGI), a single value reflecting variation within the group. The CGI for lesioned animals increased 2.3-fold relative to unlesioned animals. This study characterizes gait alterations in laboratory rats rendered ataxic by destruction of the climbing fiber pathway innervating Purkinje cells and demonstrates that a single index can be used to describe overall gait impairments. PMID:25116252

  1. Novel characterization of gait impairments in people with multiple sclerosis by means of the gait profile score.

    PubMed

    Pau, Massimiliano; Coghe, Giancarlo; Atzeni, Claudia; Corona, Federica; Pilloni, Giuseppina; Marrosu, Maria Giovanna; Cocco, Eleonora; Galli, Manuela

    2014-10-15

    The assessment of gait abnormalities in individuals with multiple sclerosis (MS) represents a key factor in evaluating the effectiveness of rehabilitation treatments. Despite the availability of sophisticated equipment to objectively evaluate the kinematic aspects of gait, there are still some difficulties in processing the large and complex amount of data they produce in the daily clinical routine. On the basis of the above-mentioned considerations we propose a novel characterization of gait kinematics in individuals with MS, based on a single measure (gait profile score, GPS) obtained from a quantitative three-dimensional analysis of gait performed using an opto-electronic system. We also investigated the correlation between GPS and the Expanded Disability Status Scale (EDSS) values. Thirty-four patients suffering from relapsing-remitting MS (13 female, 21 male, mean age 46.7 years) with an EDSS score of ≤6 underwent a gait analysis from which the GPS index was calculated. Their results were compared with those of a control group of healthy age- and gender-matched subjects. The GPS of individuals with MS was found significantly higher with respect to controls (9.12° vs. 5.67°, p<0.001) as the result of kinematic differences in gait patterns referring to pelvic tilt and rotation, hip flexion-extension and rotation, knee flexion-extension and ankle dorsi- and plantar-flexion. A moderate correlation was also found between the EDSS score of the participants and their GPS values (r = 0.63, p < 0.001). The GPS index thus appears suitable to represent gait deviations from physiological patterns in individuals affected by MS and potentially useful in assessing the outcomes related both to rehabilitation programs and pharmacologic/physical therapies. PMID:25073571

  2. Identifying clinically meaningful benchmarks for gait improvement after total hip arthroplasty.

    PubMed

    Foucher, Kharma C

    2016-01-01

    There are no established benchmarks for gait mechanics after total hip arthroplasty (THA). This study sought to identify minimum clinically important postoperative (MCIP) or minimum clinically important improvement (MCII) values for self-selected walking speed, sagittal plane dynamic hip range of motion (HROM) (peak flexion-peak extension) and peak hip adduction moments measured during quantitative gait analysis. Preoperative and 1-year postoperative data collected during quantitative gait analysis, along with Harris Hip Scores (HHS), for 145 subjects were collected from a motion analysis data repository. The MCIP (or MCII) was defined as the 75th percentile mark on a plot of the cumulative percent of subjects with HHS ≥ 80 versus the postoperative value (or change) in the respective variable. 95% confidence intervals (CI) were calculated. Logistic regression was used to test the association of age, sex, BMI, and preoperative HHS with benchmarks. The MCIP of speed was 1.34 m/s (95%CI 1.30, 1.37); MCII was 0.32 (0.30, 0.35) m/s. The HROM MCIP was 30.0° (29.4°, 30.7°); MCII was 13.3° (12.1°, 14.8°). The adduction moment MCIP was 4.2% Body Weight × Height (4.0, 4.4); MCII was 0.87 (0.57, 1.17) % Body Weight × Height. Women were more likely to achieve MCII for HROM and MCIP for adduction moment (ORs 2.4-11.6, p ≤ 0.031). Lower BMI predicted HROM and adduction moment MCIPs (ORs 0.85-0.88, p ≤ 0.015). Lower preoperative HHS predicted speed, HROM and adduction moment MCIIs (ORs 0.95-0.97, p ≤ 0.012). With further validation, clinically-relevant gait benchmarks can enhance efforts to improve THA outcomes. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:88-96, 2016. PMID:26218738

  3. Extraction of human gait signatures: an inverse kinematic approach using Groebner basis theory applied to gait cycle analysis

    NASA Astrophysics Data System (ADS)

    Barki, Anum; Kendricks, Kimberly; Tuttle, Ronald F.; Bunker, David J.; Borel, Christoph C.

    2013-05-01

    This research highlights the results obtained from applying the method of inverse kinematics, using Groebner basis theory, to the human gait cycle to extract and identify lower extremity gait signatures. The increased threat from suicide bombers and the force protection issues of today have motivated a team at Air Force Institute of Technology (AFIT) to research pattern recognition in the human gait cycle. The purpose of this research is to identify gait signatures of human subjects and distinguish between subjects carrying a load to those subjects without a load. These signatures were investigated via a model of the lower extremities based on motion capture observations, in particular, foot placement and the joint angles for subjects affected by carrying extra load on the body. The human gait cycle was captured and analyzed using a developed toolkit consisting of an inverse kinematic motion model of the lower extremity and a graphical user interface. Hip, knee, and ankle angles were analyzed to identify gait angle variance and range of motion. Female subjects exhibited the most knee angle variance and produced a proportional correlation between knee flexion and load carriage.

  4. A novel HMM distributed classifier for the detection of gait phases by means of a wearable inertial sensor network.

    PubMed

    Taborri, Juri; Rossi, Stefano; Palermo, Eduardo; Patanè, Fabrizio; Cappa, Paolo

    2014-01-01

    In this work, we decided to apply a hierarchical weighted decision, proposed and used in other research fields, for the recognition of gait phases. The developed and validated novel distributed classifier is based on hierarchical weighted decision from outputs of scalar Hidden Markov Models (HMM) applied to angular velocities of foot, shank, and thigh. The angular velocities of ten healthy subjects were acquired via three uni-axial gyroscopes embedded in inertial measurement units (IMUs) during one walking task, repeated three times, on a treadmill. After validating the novel distributed classifier and scalar and vectorial classifiers-already proposed in the literature, with a cross-validation, classifiers were compared for sensitivity, specificity, and computational load for all combinations of the three targeted anatomical segments. Moreover, the performance of the novel distributed classifier in the estimation of gait variability in terms of mean time and coefficient of variation was evaluated. The highest values of specificity and sensitivity (>0.98) for the three classifiers examined here were obtained when the angular velocity of the foot was processed. Distributed and vectorial classifiers reached acceptable values (>0.95) when the angular velocity of shank and thigh were analyzed. Distributed and scalar classifiers showed values of computational load about 100 times lower than the one obtained with the vectorial classifier. In addition, distributed classifiers showed an excellent reliability for the evaluation of mean time and a good/excellent reliability for the coefficient of variation. In conclusion, due to the better performance and the small value of computational load, the here proposed novel distributed classifier can be implemented in the real-time application of gait phases recognition, such as to evaluate gait variability in patients or to control active orthoses for the recovery of mobility of lower limb joints. PMID:25184488

  5. A Novel HMM Distributed Classifier for the Detection of Gait Phases by Means of a Wearable Inertial Sensor Network

    PubMed Central

    Taborri, Juri; Rossi, Stefano; Palermo, Eduardo; Patanè, Fabrizio; Cappa, Paolo

    2014-01-01

    In this work, we decided to apply a hierarchical weighted decision, proposed and used in other research fields, for the recognition of gait phases. The developed and validated novel distributed classifier is based on hierarchical weighted decision from outputs of scalar Hidden Markov Models (HMM) applied to angular velocities of foot, shank, and thigh. The angular velocities of ten healthy subjects were acquired via three uni-axial gyroscopes embedded in inertial measurement units (IMUs) during one walking task, repeated three times, on a treadmill. After validating the novel distributed classifier and scalar and vectorial classifiers-already proposed in the literature, with a cross-validation, classifiers were compared for sensitivity, specificity, and computational load for all combinations of the three targeted anatomical segments. Moreover, the performance of the novel distributed classifier in the estimation of gait variability in terms of mean time and coefficient of variation was evaluated. The highest values of specificity and sensitivity (>0.98) for the three classifiers examined here were obtained when the angular velocity of the foot was processed. Distributed and vectorial classifiers reached acceptable values (>0.95) when the angular velocity of shank and thigh were analyzed. Distributed and scalar classifiers showed values of computational load about 100 times lower than the one obtained with the vectorial classifier. In addition, distributed classifiers showed an excellent reliability for the evaluation of mean time and a good/excellent reliability for the coefficient of variation. In conclusion, due to the better performance and the small value of computational load, the here proposed novel distributed classifier can be implemented in the real-time application of gait phases recognition, such as to evaluate gait variability in patients or to control active orthoses for the recovery of mobility of lower limb joints. PMID:25184488

  6. Quantitative Gait Analysis Detects Significant Differences in Movement between Osteoarthritic and Nonosteoarthritic Guinea Pig Strains before and after Treatment with Flunixin Meglumine

    PubMed Central

    Santangelo, K. S.; Kaeding, A. C.; Baker, S. A.; Bertone, A. L.

    2014-01-01

    A computer-aided gait analysis system was used to contrast two guinea pig strains with differing propensity for osteoarthritis (OA), with/without administration of a nonsteroidal anti-inflammatory drug. Walking speed and static/dynamic gait parameters were determined at baseline. Flunixin meglumine was given and animals were evaluated 4, 24, and 72 hours after treatment. Body weight was compared using unpaired t-tests. Knee joints were histologically evaluated using species-specific criteria; indices were analyzed using one-way ANOVA, Kruskal-Wallis test, followed by Dunn's multiple comparisons. A generalized linear model followed by Tukey's posttests juxtaposed gait parameters; walking speed was a covariate for other outcome measures. Body weight was not different between strains; OA-prone animals demonstrated more progressive chondropathy. At baseline, OA-prone animals had slower walking speeds, narrower hind limb bases of support, shorter stride lengths, and slower limb swing speeds relative to OA-resistant animals. These differences were not detected 4 or 24 hours after treatment. By 72 hours, OA-prone animals had returned to baseline values. These findings indicate a distinct voluntary gait pattern in a rodent model of bilateral primary OA, modification of which may allow rapid screening of novel therapies. Flunixin meglumine temporarily permitted OA-prone animals to move in a manner that was analogous to OA-resistant animals. PMID:24963402

  7. Differences in cortical activation between observing one's own gait and the gait of others: a functional near-infrared spectroscopy study.

    PubMed

    Fuchigami, Takeshi; Morioka, Shu

    2015-03-01

    Using functional near-infrared spectroscopy, we investigated cortical activation while participants observed their own gait and the gait of others. Further, we compared the vividness of motor imagery induced by observing one's own and the gait of others. Participants were instructed to perform a gait observation task. The task had two conditions: observing video clips of one's own walking and observing video clips of other individuals walking. After observing the videos, the participants were asked to evaluate the vividness of the mental image of the observed gait on a visual analog scale. When observing one's own gait, the right dorsal premotor cortex and the superior parietal lobule were activated, whereas when observing the gait of others, the left inferior parietal lobule was activated. Observing one's own gait induced imagery that was significantly more vivid than that induced when viewing the gait of others. We suggest that observing one's own gait generates a representation of one's own body in the brain and induces more vivid gait imagery. PMID:25674903

  8. Coordination dynamics of (a)symmetrically loaded gait.

    PubMed

    Russell, Daniel M; Haworth, Joshua L; Martinez-Garza, Cesar

    2016-03-01

    Asymmetries in the resonant frequency of limbs/effectors lead to changes in coordination dynamics, including deviations in relative phase at ϕ = 0 or π rad and reduced stability. These effects have been successfully modeled by the extended Haken-Kelso-Bunz (HKB) coupled oscillator model (Kelso et al. in Attention and performance XIII. Erlbaum, Hillsdale, pp 139-169, 1990), and supported in laboratory tasks of rhythmic limb motions. Efforts to apply the HKB model to walking have supported the predicted deviations in phase, but not the expected decreases in coordination stability. The lack of stability effects arising from asymmetries may be due to the stabilizing influence of a treadmill or may be obscured by the balance requirements and ground impacts in gait. This study examined these possibilities by investigating walking overground with ankle weights of 3 or 6 kg to create asymmetries between the legs, as well as symmetrical loads. Participants walked without a metronome and separately with a metronome to control speed and cadence. Coordination dynamics between the legs were quantified through mean and standard deviation (SD) of ϕ, while individual leg local dynamic stability was calculated as maximum Lyapunov exponent (λ (MAX)). Irrespective of the condition, asymmetrical loads led to deviations in phase from antiphase with the loaded leg lagging behind the other, and both SDϕ and λ (MAX) increased (i.e., stability decreased). Symmetrical loads had no effect on phase deviations, but decreased stability. Overall, these findings indicate that the HKB model captures coordination dynamics in walking, but also highlights limitations in modeling the influence of loads on an individual limb. PMID:26661338

  9. Does Anxiety Cause Freezing of Gait in Parkinson's Disease?

    PubMed Central

    Ehgoetz Martens, Kaylena A.; Ellard, Colin G.; Almeida, Quincy J.

    2014-01-01

    Individuals with Parkinson's disease (PD) commonly experience freezing of gait under time constraints, in narrow spaces, and in the dark. One commonality between these different situations is that they may all provoke anxiety, yet anxiety has never been directly examined as a cause of FOG. In this study, virtual reality was used to induce anxiety and evaluate whether it directly causes FOG. Fourteen patients with PD and freezing of gait (Freezers) and 17 PD without freezing of gait (Non-Freezers) were instructed to walk in two virtual environments: (i) across a plank that was located on the ground (LOW), (ii) across a plank above a deep pit (HIGH). Multiple synchronized motion capture cameras updated participants' movement through the virtual environment in real-time, while their gait was recorded. Anxiety levels were evaluated after each trial using self-assessment manikins. Freezers performed the experiment on two separate occasions (in their ON and OFF state). Freezers reported higher levels of anxiety compared to Non-Freezers (p<0.001) and all patients reported greater levels of anxiety when walking across the HIGH plank compared to the LOW (p<0.001). Freezers experienced significantly more freezing of gait episodes (p = 0.013) and spent a significantly greater percentage of each trial frozen (p = 0.005) when crossing the HIGH plank. This finding was even more pronounced when comparing Freezers in their OFF state. Freezers also had greater step length variability in the HIGH compared to the LOW condition, while the step length variability in Non-Freezers did not change. In conclusion, this was the first study to directly compare freezing of gait in anxious and non-anxious situations. These results present strong evidence that anxiety is an important mechanism underlying freezing of gait and supports the notion that the limbic system may have a profound contribution to freezing in PD. PMID:25250691

  10. General tensor discriminant analysis and gabor features for gait recognition.

    PubMed

    Tao, Dacheng; Li, Xuelong; Wu, Xindong; Maybank, Stephen J

    2007-10-01

    The traditional image representations are not suited to conventional classification methods, such as the linear discriminant analysis (LDA), because of the under sample problem (USP): the dimensionality of the feature space is much higher than the number of training samples. Motivated by the successes of the two dimensional LDA (2DLDA) for face recognition, we develop a general tensor discriminant analysis (GTDA) as a preprocessing step for LDA. The benefits of GTDA compared with existing preprocessing methods, e.g., principal component analysis (PCA) and 2DLDA, include 1) the USP is reduced in subsequent classification by, for example, LDA; 2) the discriminative information in the training tensors is preserved; and 3) GTDA provides stable recognition rates because the alternating projection optimization algorithm to obtain a solution of GTDA converges, while that of 2DLDA does not. We use human gait recognition to validate the proposed GTDA. The averaged gait images are utilized for gait representation. Given the popularity of Gabor function based image decompositions for image understanding and object recognition, we develop three different Gabor function based image representations: 1) the GaborD representation is the sum of Gabor filter responses over directions, 2) GaborS is the sum of Gabor filter responses over scales, and 3) GaborSD is the sum of Gabor filter responses over scales and directions. The GaborD, GaborS and GaborSD representations are applied to the problem of recognizing people from their averaged gait images.A large number of experiments were carried out to evaluate the effectiveness (recognition rate) of gait recognition based on first obtaining a Gabor, GaborD, GaborS or GaborSD image representation, then using GDTA to extract features and finally using LDA for classification. The proposed methods achieved good performance for gait recognition based on image sequences from the USF HumanID Database. Experimental comparisons are made with nine state of the art classification methods in gait recognition. PMID:17699917

  11. Neural mechanisms involved in mental imagery and observation of gait.

    PubMed

    Iseki, Kazumi; Hanakawa, Takashi; Shinozaki, Jun; Nankaku, Manabu; Fukuyama, Hidenao

    2008-07-01

    Brain activity during observation and imagery of gait was investigated. Sixteen subjects were scanned with a 3-Tesla MRI scanner while viewing six types of video clips: observation of gait movement (GO) from the third-person perspective, observation of stepping movement, observation of standing posture, "virtual walking" (VW) that was observation of visual scenes mimicking the visual afferent during walking, and the scrambled version of the GO and VW stimuli. In the VW condition, moving scenes provided a virtual visual environment in which subjects easily imagined as if they were actually walking from the first-person perspective. A behavioral experiment revealed a correlation of cadence during actual walking with that during imaginary walking under the influence of the VW stimuli, indicating that a gait planning mechanism was shared by actual walking and gait imagery. The VW condition activated the dorsal premotor cortex (PMd), supplementary motor area/cingulate motor area (SMA/CMA), parahippocampal gyrus, and subcortical nuclei. The GO stimuli yielded activation of the SMA, PMd, inferior frontal gyrus, and inferior parietal lobule. Moreover, the conjunction null test of GO and VW revealed common activity in the SMA/CMA and PMd, which were reportedly active during actual gait movement, in addition to visual areas. Detailed analyses of activity during stepping or standing observation supported the specificity of the SMA and PMd to GO. These findings suggest that motor planning centers of gait, including the SMA and PMd, are activated during both imagination (first-person perspective) and observation (third-person perspective) of gait behaviors. PMID:18450480

  12. Two-dimensional PCA-based human gait identification

    NASA Astrophysics Data System (ADS)

    Chen, Jinyan; Wu, Rongteng

    2012-11-01

    It is very necessary to recognize person through visual surveillance automatically for public security reason. Human gait based identification focus on recognizing human by his walking video automatically using computer vision and image processing approaches. As a potential biometric measure, human gait identification has attracted more and more researchers. Current human gait identification methods can be divided into two categories: model-based methods and motion-based methods. In this paper a two-Dimensional Principal Component Analysis and temporal-space analysis based human gait identification method is proposed. Using background estimation and image subtraction we can get a binary images sequence from the surveillance video. By comparing the difference of two adjacent images in the gait images sequence, we can get a difference binary images sequence. Every binary difference image indicates the body moving mode during a person walking. We use the following steps to extract the temporal-space features from the difference binary images sequence: Projecting one difference image to Y axis or X axis we can get two vectors. Project every difference image in the difference binary images sequence to Y axis or X axis difference binary images sequence we can get two matrixes. These two matrixes indicate the styles of one walking. Then Two-Dimensional Principal Component Analysis(2DPCA) is used to transform these two matrixes to two vectors while at the same time keep the maximum separability. Finally the similarity of two human gait images is calculated by the Euclidean distance of the two vectors. The performance of our methods is illustrated using the CASIA Gait Database.

  13. The mental representation of the human gait in young and older adults

    PubMed Central

    Stöckel, Tino; Jacksteit, Robert; Behrens, Martin; Skripitz, Ralf; Bader, Rainer; Mau-Moeller, Anett

    2015-01-01

    The link between mental representation (MREP) structures and motor performance has been evidenced for a great variety of movement skills, but not for the human gait. Therefore the present study sought to investigate the cognitive memory structures underlying the human gait in young and older adults. In a first experiment, gait parameters at comfortable gait speed (OptoGait) were compared with gait-specific MREPs (structural dimensional analysis of MREP; SDA-M) in 36 young adults. Participants were divided into a slow- and fast-walking group. The proven relationship between gait speed and executive functions such as working memory led to the hypothesis that gait pattern and MREP differ between slow- and fast-walking adults. In a second experiment, gait performance and MREPs were compared between 24 young (27.9 years) and 24 elderly (60.1 years) participants. As age-related declines in gait performance occur from the seventh decade of life onward, we hypothesized that gait parameters would not be affected until the age of 60 years accompanied by unchanged MREP. Data of experiment one revealed that gait parameters and MREPs differed significantly between slow and fast walkers. Notably, eleven previously incurred musculoskeletal injuries were documented for the slow walkers but only two injuries and one disorder for fast walkers. Experiment two revealed no age-related differences in gait parameters or MREPs between healthy young and older adults. In conclusion, the differences in gait parameters associated with lower comfortable gait speeds are reflected by differences in MREPs, whereby SDA-M data indicate that the single limb support phase may serve as a critical functional period. These differences probably resulted from previously incurred musculoskeletal injuries. Our data further indicate that the human gait and its MREP are stable until the age of 60. SDA-M may be considered as a valuable clinical tool for diagnosis of gait abnormalities and monitoring of therapeutic effectiveness. PMID:26236249

  14. Physiological evaluation of gait disturbances post stroke.

    PubMed

    Lamontagne, Anouk; Stephenson, Jennifer L; Fung, Joyce

    2007-04-01

    A large proportion of stroke survivors have to deal with problems in mobility. Proper evaluations must be undertaken to understand the sensorimotor impairments underlying locomotor disorders post stroke, so that evidence-based interventions can be developed. The current electrophysiological, biomechanical, and imagery evaluations that provide insight into locomotor dysfunction post stroke, as well as their advantages and limitations, are reviewed in this paper. In particular, electrophysiological evaluations focus on the contrast of electromyographic patterns and integrity of spinal reflex pathways during perturbed and unperturbed locomotion between persons with stroke and healthy individuals. At a behavioral level, biomechanical evaluations that include temporal distance factors, kinematic and kinetic analyses, as well as the mechanical energy and metabolic cost, are useful when combined with electrophysiological measures for the interpretation of gait disturbances that are related to the control of the central nervous system or secondary to biomechanical constraints. Finally, current methods in imaging and transcranial magnetic stimulation can provide further insight into cortical control of locomotion and the integrity of the corticospinal pathways. PMID:17307395

  15. Clumping Properties of Content-Bearing Words.

    ERIC Educational Resources Information Center

    Bookstein, A.; Klein, S. T.; Raita, T.

    1998-01-01

    Defines the notion of serial clustering of words in text, and explores the value of such clustering as an indicator of a word's bearing content. This approach is flexible in the sense that it is context-sensitive; a numerical approach may also be of value in assigning weights to terms in requests. Experimental support is obtained from natural text…

  16. Bears Arouse Interest in Microbiota's Role in Health.

    PubMed

    Dill-McFarland, Kimberly A; Suen, Garret; Carey, Hannah V

    2016-04-01

    The first report of the effect of hibernation on the gut microbiota of bears reveals trends both similar and distinct from those found in small hibernators. A model mouse system also suggested possible roles of the microbiota for healthy weight gain and insulin tolerance in bears during their active season. PMID:26873548

  17. Effect of Rhythmic Auditory Stimulation on Gait in Parkinsonian Patients with and without Freezing of Gait

    PubMed Central

    Arias, Pablo; Cudeiro, Javier

    2010-01-01

    Freezing of gait (FOG) in Parkinson's disease (PD) rises in prevalence when the effect of medications decays. It is known that auditory rhythmic stimulation improves gait in patients without FOG (PD-FOG), but its putative effect on patients with FOG (PD+FOG) at the end of dose has not been evaluated yet. This work evaluates the effect of auditory rhythmic stimulation on PD+FOG at the end of dose. 10 PD+FOG and 9 PD-FOG patients both at the end of dose periods, and 10 healthy controls were asked to perform several walking tasks. Tasks were performed in the presence and absence of auditory sensory stimulation. All PD+FOG suffered FOG during the task. The presence of auditory rhythmic stimulation (10% above preferred walking cadence) led PD+FOG to significantly reduce FOG. Velocity and cadence were increased, and turn time reduced in all groups. We conclude that auditory stimulation at the frequency proposed may be useful to avoid freezing episodes in PD+FOG. PMID:20339591

  18. Principal Component Analysis of gait in Parkinson's disease: relevance of gait velocity.

    PubMed

    Dillmann, Ulrich; Holzhoffer, Claudia; Johann, Yvonne; Bechtel, Sabrina; Gräber, Stefan; Massing, Christoph; Spiegel, Jörg; Behnke, Stefanie; Bürmann, Jan; Louis, Alfred K

    2014-03-01

    Principal Component Analysis (PCA) is a method to estimate the relation between data points. We used PCA to analyse movements of the upper and lower extremities during treadmill walking in healthy subjects and two groups of Parkinsonian patients. Healthy subjects (n=35) showed a typical pattern with high values of PC1 and low values in a descending order of PC2-PC4. Increase of speed resulted in a significant increase of PC1 and a significant decrease of the following PC's. In more severely affected patients (n=19, UPDRS>20), PC1 was significantly decreased and PC2-PC4 were significantly increased compared to healthy subjects. Speed could be increased only within a small range without corresponding changes of the PC's. In less severely affected patients (n=17), significant differences of the PC's were only found with fast pace. Separate analysis of arms and legs revealed that these changes are only due to altered movements of the arm. Analysis of the pattern of PC's in response to changes of gait velocities reveal alterations even in less severely affected Parkinsonian patients. The changes of the PC's with higher gait velocities in healthy subjects are suggestive of an increase of intersegmental coordination. This is impaired even in less severely affected Parkinsonian patients. PMID:24374062

  19. Bearings: Technology and needs

    NASA Technical Reports Server (NTRS)

    Anderson, W. J.

    1982-01-01

    A brief status report on bearing technology and present and near-term future problems that warrant research support is presented. For rolling element bearings a material with improved fracture toughness, life data in the low Lambda region, a comprehensive failure theory verified by life data and incorporated into dynamic analyses, and an improved corrosion resistant alloy are perceived as important needs. For hydrodynamic bearings better definition of cavitation boundaries and pressure distributions for squeeze film dampers, and geometry optimization for minimum power loss in turbulent film bearings are needed. For gas film bearings, foil bearing geometries that form more nearly optimum film shapes for maximum load capacity, and more effective surface protective coatings for high temperature operation are needed.

  20. Combined robotic-aided gait training and 3D gait analysis provide objective treatment and assessment of gait in children and adolescents with Acquired Hemiplegia.

    PubMed

    Molteni, Erika; Beretta, Elena; Altomonte, Daniele; Formica, Francesca; Strazzer, Sandra

    2015-08-01

    To evaluate the feasibility of a fully objective rehabilitative and assessment process of the gait abilities in children suffering from Acquired Hemiplegia (AH), we studied the combined employment of robotic-aided gait training (RAGT) and 3D-Gait Analysis (GA). A group of 12 patients with AH underwent 20 sessions of RAGT in addition to traditional manual physical therapy (PT). All the patients were evaluated before and after the training by using the Gross Motor Function Measures (GMFM), the Functional Assessment Questionnaire (FAQ), and the 6 Minutes Walk Test. They also received GA before and after RAGT+PT. Finally, results were compared with those obtained from a control group of 3 AH children who underwent PT only. After the training, the GMFM and FAQ showed significant improvement in patients receiving RAGT+PT. GA highlighted significant improvement in stance symmetry and step length of the affected limb. Moreover, pelvic tilt increased, and hip kinematics on the sagittal plane revealed statistically significant increase in the range of motion during the hip flex-extension. Our data suggest that the combined program RAGT+PT induces improvements in functional activities and gait pattern in children with AH, and it demonstrates that the combined employment of RAGT and 3D-GA ensures a fully objective rehabilitative program. PMID:26737310

  1. An electric motor with magnetic bearings: A concept

    NASA Technical Reports Server (NTRS)

    Studer, P. A.

    1973-01-01

    Because same magnetic flux is used to control rotor as to drive it, size, weight, and power required are minimized. Constant total current keeps motor torque invarient, and absence of mechanical bearings eliminates wear and reduces frictional power loss.

  2. Bear Spray Safety Program

    USGS Publications Warehouse

    Blome, C.D.; Kuzniar, R.L.

    2009-01-01

    A bear spray safety program for the U.S. Geological Survey (USGS) was officially initiated by the Firearms Safety Committee to address accident prevention and to promote personnel training in bear spray and its transportation, storage, and use for defense against wild animals. Used as part of a system including firearms, or used alone for those who choose not to carry a firearm, bear spray is recognized as an effective tool that can prevent injury in a wild animal attack.

  3. A comparative collision-based analysis of human gait

    PubMed Central

    Lee, David V.; Comanescu, Tudor N.; Butcher, Michael T.; Bertram, John E. A.

    2013-01-01

    This study compares human walking and running, and places them within the context of other mammalian gaits. We use a collision-based approach to analyse the fundamental dynamics of the centre of mass (CoM) according to three angles derived from the instantaneous force and velocity vectors. These dimensionless angles permit comparisons across gait, species and size. The collision angle ?, which is equivalent to the dimensionless mechanical cost of transport CoTmech, is found to be three times greater during running than walking of humans. This threefold difference is consistent with previous studies of walking versus trotting of quadrupeds, albeit tends to be greater in the gaits of humans and hopping bipeds than in quadrupeds. Plotting the collision angle ? together with the angles of the CoM force vector ? and velocity vector ? results in the functional grouping of bipedal and quadrupedal gaits according to their CoM dynamicswalking, galloping and ambling are distinguished as separate gaits that employ collision reduction, whereas trotting, running and hopping employ little collision reduction and represent more of a continuum that is influenced by dimensionless speed. Comparable with quadrupedal mammals, collision fraction (the ratio of actual to potential collision) is 0.51 during walking and 0.89 during running, indicating substantial collision reduction during walking, but not running, of humans. PMID:24089334

  4. Rhythmic auditory stimulation in gait training for Parkinson's disease patients.

    PubMed

    Thaut, M H; McIntosh, G C; Rice, R R; Miller, R A; Rathbun, J; Brault, J M

    1996-03-01

    Rhythmic auditory stimulation (RAS) was used as a pacemaker during a 3-week home-based gait-training program for Parkinson's disease (PD) patients (n = 15). Electromyogram (EMG) patterns and stride parameters were assessed before and after the test without RAS to evaluate changes in gait patterns. Data were compared with those of two control groups (n = 11), who either did not participate in any gait training or who participated in an internally self-paced training program. RAS consisted of audiotapes with metronome-pulse patterns embedded into the on/off beat structure of rhythmically accentuated instrumental music. Patients who trained with RAS significantly (p < 0.05) improved their gait velocity by 25%, stride length by 12%, and step cadence by 10% more than self-paced subjects who improved their velocity by 7% and no-training subjects whose velocity decreased by 7%. In the RAS-group, timing of EMG patterns changed significantly (p < 0.05) in the anterior tibialis and vastus lateralis muscles. Evidence for rhythmic entrainment of gait patterns was shown by the ability of the RAS group to reproduce the speed of the last training tape within a 2% margin of error without RAS. PMID:8684391

  5. Secure and privacy enhanced gait authentication on smart phone.

    PubMed

    Hoang, Thang; Choi, Deokjai

    2014-01-01

    Smart environments established by the development of mobile technology have brought vast benefits to human being. However, authentication mechanisms on portable smart devices, particularly conventional biometric based approaches, still remain security and privacy concerns. These traditional systems are mostly based on pattern recognition and machine learning algorithms, wherein original biometric templates or extracted features are stored under unconcealed form for performing matching with a new biometric sample in the authentication phase. In this paper, we propose a novel gait based authentication using biometric cryptosystem to enhance the system security and user privacy on the smart phone. Extracted gait features are merely used to biometrically encrypt a cryptographic key which is acted as the authentication factor. Gait signals are acquired by using an inertial sensor named accelerometer in the mobile device and error correcting codes are adopted to deal with the natural variation of gait measurements. We evaluate our proposed system on a dataset consisting of gait samples of 34 volunteers. We achieved the lowest false acceptance rate (FAR) and false rejection rate (FRR) of 3.92% and 11.76%, respectively, in terms of key length of 50 bits. PMID:24955403

  6. Knee muscle strength in multiple sclerosis: relationship with gait characteristics

    PubMed Central

    Güner, Senem; Hagharı, Sema; Inanıcı, Fatma; Alsancak, Serap; Aytekın, Gokhan

    2015-01-01

    [Purpose] To investigate the relationship between isokinetic knee muscle strength and kinematic, kinetic and spatiotemporal gait parameters of patients with multiple sclerosis (MS). [Subjects and Methods] Twenty-nine MS patients (mean age 31.5±6.5) were investigated in this study. The isokinetic knee muscle strength and gait parameters of MS patients with moderate and severe disability, as determined by the expanded disability status scale (EDSS): EDSS=1–4.5 (n=22, moderate disability) and EDSS>4.5 (n=7, severe disability) were measured. [Results] Isokinetic knee muscle strength, kinematic, kinetic and spatiotemporal gait parameters differed between moderate (EDSS=1–4.5, n=22) and severe disability (EDSS>4.5, n=7). The correlation between each of gait speed, stride length, total range of knee joint movement and the four strength parameters (minimum and maximum quadriceps and hamstring muscle strengths) were significant for the MS group as a whole. Within subgroups, the correlation between minimum hamstring strength and total range of knee movement was significant only in group EDSS>4.5; minimum hamstring correlated with peak knee extensor moment in group EDSS=1–4.5, but at a reduced level of significance. [Conclusion] The present study revealed significant correlations between gait characteristics and isokinetic strength parameters of the quadriceps and hamstring muscles. Our study suggests that rehabilitation protocols for MS patients should include a critical strength training programme particularly for the hamstring and quadriceps muscles. PMID:25931736

  7. Secure and Privacy Enhanced Gait Authentication on Smart Phone

    PubMed Central

    Choi, Deokjai

    2014-01-01

    Smart environments established by the development of mobile technology have brought vast benefits to human being. However, authentication mechanisms on portable smart devices, particularly conventional biometric based approaches, still remain security and privacy concerns. These traditional systems are mostly based on pattern recognition and machine learning algorithms, wherein original biometric templates or extracted features are stored under unconcealed form for performing matching with a new biometric sample in the authentication phase. In this paper, we propose a novel gait based authentication using biometric cryptosystem to enhance the system security and user privacy on the smart phone. Extracted gait features are merely used to biometrically encrypt a cryptographic key which is acted as the authentication factor. Gait signals are acquired by using an inertial sensor named accelerometer in the mobile device and error correcting codes are adopted to deal with the natural variation of gait measurements. We evaluate our proposed system on a dataset consisting of gait samples of 34 volunteers. We achieved the lowest false acceptance rate (FAR) and false rejection rate (FRR) of 3.92% and 11.76%, respectively, in terms of key length of 50 bits. PMID:24955403

  8. Why we should study gait initiation in Parkinson's disease.

    PubMed

    Delval, A; Tard, C; Defebvre, L

    2014-01-01

    The gait initiation process is of particular interest in Parkinson's disease because it combines motor and cognitive components of movement preparation (referred to as anticipatory postural adjustments) and movement execution (the step by itself). Moreover, gait initiation in Parkinson's disease is often affected by motor blocks (a subtype of the "freezing of gait" phenomenon). Gait initiation disturbances in Parkinson's disease include delayed release of anticipatory postural adjustments, hypokinetic anticipatory postural adjustments (reduced scaling) and bradykinetic anticipatory postural adjustments (abnormal timing). The most extreme form is freezing of gait with sometimes the absence of anticipatory postural adjustments. Other phenomena can be also described in some freezing patients (such as multiple anticipatory postural adjustments, described clinically as "knee trembling"). The fact that emotion, attention, external triggers and dopaminergic drugs can all modify this motor program suggests the existence of a complex pathophysiological mechanism that involves not only locomotor networks but also cortical areas and the basal ganglia system. Abnormal coupling between standing posture and anticipatory postural adjustments and between the latter and step execution appears to be a crucial part of the pathophysiological mechanism. Although external cueing appears to be of interest, few studies have provided evidence of the efficacy of various rehabilitation methods in routine care. PMID:24502907

  9. Dynamic markers of altered gait rhythm in amyotrophic lateral sclerosis

    NASA Technical Reports Server (NTRS)

    Hausdorff, J. M.; Lertratanakul, A.; Cudkowicz, M. E.; Peterson, A. L.; Kaliton, D.; Goldberger, A. L.

    2000-01-01

    Amyotrophic lateral sclerosis (ALS) is a disorder marked by loss of motoneurons. We hypothesized that subjects with ALS would have an altered gait rhythm, with an increase in both the magnitude of the stride-to-stride fluctuations and perturbations in the fluctuation dynamics. To test for this locomotor instability, we quantitatively compared the gait rhythm of subjects with ALS with that of normal controls and with that of subjects with Parkinson's disease (PD) and Huntington's disease (HD), pathologies of the basal ganglia. Subjects walked for 5 min at their usual pace wearing an ankle-worn recorder that enabled determination of the duration of each stride and of stride-to-stride fluctuations. We found that the gait of patients with ALS is less steady and more temporally disorganized compared with that of healthy controls. In addition, advanced ALS, HD, and PD were associated with certain common, as well as apparently distinct, features of altered stride dynamics. Thus stride-to-stride control of gait rhythm is apparently compromised with ALS. Moreover, a matrix of markers based on gait dynamics may be useful in characterizing certain pathologies of motor control and, possibly, in quantitatively monitoring disease progression and evaluating therapeutic interventions.

  10. Bearing restoration by grinding

    NASA Technical Reports Server (NTRS)

    Hanau, H.; Parker, R. J.; Zaretsky, E. V.; Chen, S. M.; Bull, H. L.

    1976-01-01

    A joint program was undertaken by the NASA Lewis Research Center and the Army Aviation Systems Command to restore by grinding those rolling-element bearings which are currently being discarded at aircraft engine and transmission overhaul. Three bearing types were selected from the UH-1 helicopter engine (T-53) and transmission for the pilot program. No bearing failures occurred related to the restoration by grinding process. The risk and cost of a bearing restoration by grinding programs was analyzed. A microeconomic impact analysis was performed.

  11. Perception of gait patterns that deviate from normal and symmetric biped locomotion.

    PubMed

    Handžić, Ismet; Reed, Kyle B

    2015-01-01

    This study examines the range of gait patterns that are perceived as healthy and human-like with the goal of understanding how much asymmetry is allowable in a gait pattern before other people start to notice a gait impairment. Specifically, this study explores if certain abnormal walking patterns can be dismissed as unimpaired or not uncanny. Altering gait biomechanics is generally done in the fields of prosthetics and rehabilitation, however the perception of gait is often neglected. Although a certain gait can be functional, it may not be considered as normal by observers. On the other hand, an abnormally perceived gait may be more practical or necessary in some situations, such as limping after an injury or stroke and when wearing a prosthesis. This research will help to find the balance between the form and function of gait. Gait patterns are synthetically created using a passive dynamic walker (PDW) model that allows gait patterns to be systematically changed without the confounding influence from human sensorimotor feedback during walking. This standardized method allows the perception of specific changes in gait to be studied. The PDW model was used to produce walking patterns that showed a degree of abnormality in gait cadence, knee height, step length, and swing time created by changing the foot roll-over-shape, knee damping, knee location, and leg masses. The gait patterns were shown to participants who rated them according to separate scales of impairment and uncanniness. The results indicate that some pathological and asymmetric gait patterns are perceived as unimpaired and normal. Step time and step length asymmetries less than 5%, small knee location differences, and gait cadence changes of 25% do not result in a change in perception. The results also show that the parameters of a pathologically or uncanny perceived gait can be beneficially altered by increasing other independent parameters, in some sense masking the initial pathology. PMID:25774144

  12. Perception of gait patterns that deviate from normal and symmetric biped locomotion

    PubMed Central

    Handžić, Ismet; Reed, Kyle B.

    2015-01-01

    This study examines the range of gait patterns that are perceived as healthy and human-like with the goal of understanding how much asymmetry is allowable in a gait pattern before other people start to notice a gait impairment. Specifically, this study explores if certain abnormal walking patterns can be dismissed as unimpaired or not uncanny. Altering gait biomechanics is generally done in the fields of prosthetics and rehabilitation, however the perception of gait is often neglected. Although a certain gait can be functional, it may not be considered as normal by observers. On the other hand, an abnormally perceived gait may be more practical or necessary in some situations, such as limping after an injury or stroke and when wearing a prosthesis. This research will help to find the balance between the form and function of gait. Gait patterns are synthetically created using a passive dynamic walker (PDW) model that allows gait patterns to be systematically changed without the confounding influence from human sensorimotor feedback during walking. This standardized method allows the perception of specific changes in gait to be studied. The PDW model was used to produce walking patterns that showed a degree of abnormality in gait cadence, knee height, step length, and swing time created by changing the foot roll-over-shape, knee damping, knee location, and leg masses. The gait patterns were shown to participants who rated them according to separate scales of impairment and uncanniness. The results indicate that some pathological and asymmetric gait patterns are perceived as unimpaired and normal. Step time and step length asymmetries less than 5%, small knee location differences, and gait cadence changes of 25% do not result in a change in perception. The results also show that the parameters of a pathologically or uncanny perceived gait can be beneficially altered by increasing other independent parameters, in some sense masking the initial pathology. PMID:25774144

  13. Effect of virtual reality games on stroke patients’ balance, gait, depression, and interpersonal relationships

    PubMed Central

    Song, Gui bin; Park, Eun cho

    2015-01-01

    [Purpose] The purpose of the study was to determine the effects of training using virtual reality games on balance and gait ability, as well as the psychological characteristics of stroke patients, such as depression and interpersonal relationships, by comparing them with the effects of ergometer training. [Subjects] Forty stroke patients were randomly divided into a virtual reality group (VRG, N = 20) and an ergometer training group (ETG, N = 20). [Methods] VRG performed training using the Xbox Kinect. ETG performed training using an ergometer bicycle. Both groups received training 30 min per day, five times per week, for eight weeks. [Results] Both the VRG and ETG subjects exhibited a significant difference in weight distribution ratio on the paralyzed side and balance ability. Both the VRG and ETG patients showed significant improvement in psychological measures BDI and RCS, after the intervention, and the VRG sowed a more significant increase in BDI than the ETG. [Conclusion] According to the result of this study, virtual reality training and ergometer training were both effective at improving balance, gait abilities, depression, and interpersonal relationships among stroke patients. PMID:26311925

  14. Use of a backpack alters gait initiation of high school students.

    PubMed

    Vieira, Marcus Fraga; Lehnen, Georgia Cristina; Noll, Matias; Rodrigues, Fábio Barbosa; de Avelar, Ivan Silveira; da Costa, Paula Hentschel Lobo

    2016-06-01

    We assessed how backpack carriage influences the gait initiation (GI) process in high school students, who extensively use backpacks. GI involves different dynamics from gait itself, while the excessive use of backpacks can result in adverse effects. 117 high school students were evaluated in three experimental conditions: no backpack (NB), bilateral backpack (BB), and unilateral backpack (UB). Two force plates were used to acquire ground reaction forces (GRFs) and moments for each foot separately. Center of pressure (COP) scalar variables were extracted, and statistical parametric mapping analysis was performed over the entire COP/GRFs time series. GI anticipatory postural adjustments (APAs) were reduced and were faster in backpack conditions; medial-lateral COP excursion was smaller in this phase. The uneven distribution of the extra load in the UB condition led to a larger medial-lateral COP shift in the support-foot unloading phase, with a corresponding vertical GRF change that suggests a more pronounced unloading swing foot/loading support foot mechanism. The anterior-posterior GRFs were altered, but the COP was not. A possible explanation for these results may be the forward trunk lean and the center of mass proximity of the base of support boundary, which induced smaller and faster APA, increased swing foot/support foot weight transfer, and increased load transfer to the first step. PMID:27088395

  15. Influence of Body Composition on Gait Kinetics throughout Pregnancy and Postpartum Period

    PubMed Central

    Branco, Marco; Santos-Rocha, Rita; Vieira, Filomena; Silva, Maria-Raquel; Aguiar, Liliana; Veloso, António P.

    2016-01-01

    Pregnancy leads to several changes in body composition and morphology of women. It is not clear whether the biomechanical changes occurring in this period are due exclusively to body composition and size or to other physiological factors. The purpose was to quantify the morphology and body composition of women throughout pregnancy and in the postpartum period and identify the contribution of these parameters on the lower limb joints kinetic during gait. Eleven women were assessed longitudinally, regarding anthropometric, body composition, and kinetic parameters of gait. Body composition and body dimensions showed a significant increase during pregnancy and a decrease in the postpartum period. In the postpartum period, body composition was similar to the 1st trimester, except for triceps skinfold, total calf area, and body mass index, with higher results than at the beginning of pregnancy. Regression models were developed to predict women's internal loading through anthropometric variables. Four models include variables associated with the amount of fat; four models include variables related to overall body weight; three models include fat-free mass; one model includes the shape of the trunk as a predictor variable. Changes in maternal body composition and morphology largely determine kinetic dynamics of the joints in pregnant women. PMID:27073713

  16. Estimate of lower trunk angles in pathological gaits using gyroscope data.

    PubMed

    Grimpampi, Eleni; Bonnet, Vincent; Taviani, Antonio; Mazzà, Claudia

    2013-07-01

    Trunk mobility impairment can cause balance, postural and gait challenges during overground level walking in patients with different pathologies. Assessment of the rotations of the trunk during walking with an abnormal gait can provide knowledge required for a better understanding of the nature of the motor control deficit and support decision-making in patient rehabilitation. A method based on the use of a weighted Fourier linear combiner (WFLC) adaptive filter is proposed in this paper for the estimation of lower trunk angles during pathological overground level walking, using angular velocities measured at the lower trunk level with a wearable inertial sensor. This method was validated for a group of 24 patients, 13 with hemiplegia and 11 with Parkinson's disease, by comparing the estimated angles to those simultaneously obtained from a stereophotogrammetric system. Analysis of the root mean square error, correlation coefficient and offset results revealed that the WFLC approach is highly accurate in estimating lateral and frontal bending and axial rotations of the lower trunk in pathological level walking. PMID:23497803

  17. Effect of virtual reality games on stroke patients' balance, gait, depression, and interpersonal relationships.

    PubMed

    Song, Gui Bin; Park, Eun Cho

    2015-07-01

    [Purpose] The purpose of the study was to determine the effects of training using virtual reality games on balance and gait ability, as well as the psychological characteristics of stroke patients, such as depression and interpersonal relationships, by comparing them with the effects of ergometer training. [Subjects] Forty stroke patients were randomly divided into a virtual reality group (VRG, N = 20) and an ergometer training group (ETG, N = 20). [Methods] VRG performed training using the Xbox Kinect. ETG performed training using an ergometer bicycle. Both groups received training 30 min per day, five times per week, for eight weeks. [Results] Both the VRG and ETG subjects exhibited a significant difference in weight distribution ratio on the paralyzed side and balance ability. Both the VRG and ETG patients showed significant improvement in psychological measures BDI and RCS, after the intervention, and the VRG sowed a more significant increase in BDI than the ETG. [Conclusion] According to the result of this study, virtual reality training and ergometer training were both effective at improving balance, gait abilities, depression, and interpersonal relationships among stroke patients. PMID:26311925

  18. Development of an affordable system for 2D kinematics and dynamics analysis of human gait

    NASA Astrophysics Data System (ADS)

    Mahyuddin, A. I.; Mihradi, S.; Dirgantara, T.; Sukmajaya, A.; Juliyad, N.; Purba, U.

    2009-12-01

    Development of a low-cost, yet reliable, system for 2D gait analysis is presented in this paper. The system consists of a home video camera with speed of 25 fps, LED markers, PC and a technical computing software, which are used for capturing and processing the digital image of markers attached to human body during motion. In the experiments, a person is instructed to walk in a specially arranged measurement area. The recorded images are then digitally processed to detect and track the 2D coordinate of the markers over time. To conduct a dynamics analysis, a mathematical formulation for human motion is constructed where the body is modeled by a system of five rigid bars connected by joints. Finally, a program is developed to plot and calculate the kinematics and dynamics data of human gait, where the markers position data over time, and other variables such as dimensions and weight of the body are used as the input in the program.

  19. Development of an affordable system for 2D kinematics and dynamics analysis of human gait

    NASA Astrophysics Data System (ADS)

    Mahyuddin, A. I.; Mihradi, S.; Dirgantara, T.; Sukmajaya, A.; Juliyad, N.; Purba, U.

    2010-03-01

    Development of a low-cost, yet reliable, system for 2D gait analysis is presented in this paper. The system consists of a home video camera with speed of 25 fps, LED markers, PC and a technical computing software, which are used for capturing and processing the digital image of markers attached to human body during motion. In the experiments, a person is instructed to walk in a specially arranged measurement area. The recorded images are then digitally processed to detect and track the 2D coordinate of the markers over time. To conduct a dynamics analysis, a mathematical formulation for human motion is constructed where the body is modeled by a system of five rigid bars connected by joints. Finally, a program is developed to plot and calculate the kinematics and dynamics data of human gait, where the markers position data over time, and other variables such as dimensions and weight of the body are used as the input in the program.

  20. Weight Control

    MedlinePlus

    ... obese. Achieving a healthy weight can help you control your cholesterol, blood pressure and blood sugar. It ... use more calories than you eat. A weight-control strategy might include Choosing low-fat, low-calorie ...

  1. Effect of footwear on minimum foot clearance, heel slippage and spatiotemporal measures of gait in older women.

    PubMed

    Davis, Annette M; Galna, Brook; Murphy, Anna T; Williams, Cylie M; Haines, Terry P

    2016-02-01

    Footwear has been implicated as a factor in falls, which is a major issue affecting the health of older adults. This study investigated the effect of footwear with dorsal fixation, slippers and bare feet on minimum foot clearance, heel slippage and spatiotemporal variables of gait in community dwelling older women. Thirty women participated (mean age (SD) 69.1 (5.1) years) in a gait assessment using the GaitRITE and Vicon 612 motion analysis system. Conditions included footwear with dorsal fixation, slippers or bare feet. Footwear with dorsal fixation resulted in improved minimum foot clearance compared to the slippers and bare feet conditions and less heel slippage than slippers and an increase in double support. These features lend weight to the argument that older women should be supported to make footwear choices with optimal fitting features including dorsal fixation. Recommendations of particular styles and features of footwear may assist during falls prevention education to reduce the incidence of foot trips and falls. PMID:27004631

  2. Gait pattern differences between children with mild scoliosis and children with unilateral cerebral palsy.

    PubMed

    Domagalska-Szopa, Małgorzata; Szopa, Andrzej

    2014-01-01

    This study was conducted to investigate the effects of asymmetrical body posture alone, i.e., the effects seen in children with mild scoliosis, vs. the effects of body posture control impairment, i.e., those seen in children with unilateral cerebral palsy on gait patterns. Three-dimensional instrumented gait analysis (3DGA) was conducted in 45 children with hemiplegia and 51 children with mild scoliosis. All the children were able to walk without assistance devices. A set of 35 selected spatiotemporal gait and kinematics parameters were evaluated when subjects walked on a treadmill. A cluster analysis revealed 3 different gait patterns: a scoliotic gait pattern and 2 different hemiplegic gait patterns. The results showed that the discrepancy in gait patterns was not simply a lower limb kinematic deviation in the sagittal plane, as expected. Additional altered kinematics, such as pelvic misorientation in the coronal plane in both the stance and swing phases and inadequate stance phase hip ad/abduction, which resulted from postural pattern features, were distinguished between the 3 gait patterns. Our study provides evidence for a strong correlation between postural and gait patterns in children with unilateral cerebral palsy. Information on differences in gait patterns may be used to improve the guidelines for early therapy for children with hemiplegia before abnormal gait patterns are fully established. The gait pathology characteristic of scoliotic children is a potential new direction for treating scoliosis that complements the standard posture and walking control therapy exercises with the use of biofeedback. PMID:25089908

  3. A Review of Balance and Gait Capacities in Relation to Falls in Persons with Intellectual Disability

    ERIC Educational Resources Information Center

    Enkelaar, Lotte; Smulders, Ellen; van Schrojenstein Lantman-de Valk, Henny; Geurts, Alexander C. H.; Weerdesteyn, Vivian

    2012-01-01

    Limitations in mobility are common in persons with intellectual disabilities (ID). As balance and gait capacities are key aspects of mobility, the prevalence of balance and gait problems is also expected to be high in this population. The objective of this study was to critically review the available literature on balance and gait characteristics…

  4. Gait variability in people with neurological disorders: A systematic review and meta-analysis.

    PubMed

    Moon, Yaejin; Sung, JongHun; An, Ruopeng; Hernandez, Manuel E; Sosnoff, Jacob J

    2016-06-01

    There has been growing evidence showing gait variability provides unique information about gait characteristics in neurological disorders. This study systemically reviewed and quantitatively synthesized (via meta-analysis) existing evidence on gait variability in various neurological diseases, including Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), cerebellar ataxia (CA), Huntington's disease (HD), multiple sclerosis (MS), and Parkinson's disease (PD). Keyword search were conducted in PubMed, Web of science, Cumulative Index to Nursing and Allied Health Literature, and Cochrane Library. Meta-analysis was performed to estimate the pooled effect size for gait variability for each neurological group. Meta-regression was performed to compare gait variability across multiple groups with neurological diseases. Gait variability of 777 patients with AD, ALS, CA, HD, MS, or PD participating in 25 studies was included in meta-analysis. All pathological groups had increased amount of gait variability and loss of fractal structure of gait dynamics compared to healthy controls, and gait variability differentiated distinctive neurological conditions. The HD groups had the highest alterations in gait variability among all pathological groups, whereas the PD, AD and MS groups had the lowest. Interventions that aim to improve gait function in patients with neurological disorders should consider the heterogeneous relationship between gait variability and neurological conditions. PMID:27023045

  5. Effect of Task Specific Exercises, Gait Training, and Visual Biofeedback on Equinovarus Gait among Individuals with Stroke: Randomized Controlled Study

    PubMed Central

    Khallaf, Mohamed Elsayed; Gabr, Ahmed Maher; Fayed, Eman Elsayed

    2014-01-01

    Background and Purpose. Equinovarus foot is a common sign after stroke. The aim of this study is to investigate the effect of task specific exercises, gait training, and visual biofeedback on correcting equinovarus gait among individuals with stroke. Subjects and Methods. Sixteen subjects with ischemic stroke were randomly assigned to two equal groups (G1 and G2). All the patients were at stage 4 of motor recovery of foot according to Chedoke-McMaster Stroke Assessment without any cognitive dysfunction. E-med pedography was used to measure contact time, as well as force underneath hind and forefoot during walking. Outcome measures were collected before randomization, one week after the last session, and four weeks later. Participants